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Ex_07_Geotech_Report
DR A F T SUBMITTED TO: Carollo Engineers, Inc. 1250 5th Avenue, Suite 900 Seattle, WA 98101 BY: Shannon & Wilson 400 N 34th Street, Suite 100 Seattle, WA 98103 (206) 632-8020 www.shannonwilson.com GEOTECHNICAL ENGINEERING REPORT Kennydale Lakeline Sewer Improvements RENTON, WASHINGTON December 6, 2024 Shannon & Wilson No: 104024-200 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 12/6/2024-104024-200-R1-Rev/wp/tvv i Submitted To: Carollo Engineers, Inc. 1250 5th Avenue, Suite 900 Seattle, WA 98101 Attn: Erik Waligorski Subject: DRAFT GEOTECHNICAL ENGINEERING REPORT, KENNYDALE LAKELINE SEWER IMPROVEMENTS, RENTON, WASHINGTON Shannon & Wilson prepared this report and participated in this project as a subconsultant to Carollo Engineers, Inc. Our scope of services was specified in Task Order No. 1, dated December 19, 2023, with Carollo Engineers, and was authorized by Erik Waligorski. This report presents the results of subsurface explorations, engineering analysis, and geotechnical recommendations for the design of the project and was prepared by the undersigned. We appreciate the opportunity to be of service to you on this project. If you have questions concerning this report, or we may be of further service, please contact us. Sincerely, SHANNON & WILSON Thomas Keatts, PE Senior Engineer Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 ii CO N T E N T S CONTENTS 1 Introduction ................................................................................................................................ 1 2 Site and Project Description ...................................................................................................... 1 2.1 Geologic Setting ................................................................................................................ 2 2.2 Holocene Deposits ........................................................................................................... 3 2.3 Vashon Glacial Deposits.................................................................................................. 3 2.3.1 Vashon Recessional Glacial Deposits ............................................................... 3 2.3.2 Glacially Overridden Vashon Glacial Deposits .............................................. 3 2.3.3 Glacially Overridden Pre-Vashon Deposits .................................................... 4 3 Subsurface Explorations ............................................................................................................ 4 4 Laboratory Testing ..................................................................................................................... 5 5 Existing Data Review ................................................................................................................. 6 6 Subsurface Conditions ............................................................................................................... 7 7 Seismic Conditions ..................................................................................................................... 9 7.1 Seismic Design .................................................................................................................. 9 7.2 Liquefaction Potential .................................................................................................... 10 8 Slope Stability Analysis ........................................................................................................... 10 9 Geotechnical Recommendations ............................................................................................ 11 9.1 ILS Foundations.............................................................................................................. 12 9.1.1 Bearing Capacity................................................................................................ 13 9.1.2 Settlement ........................................................................................................... 13 9.2 Generator Foundation ................................................................................................... 13 9.3 Slope Stabilization .......................................................................................................... 14 9.4 ILS Excavation and Temporary Shoring ..................................................................... 15 9.5 Sewer Main and Lateral Excavation and Temporary Shoring ................................. 16 9.6 Trenchless Alternative for ILS Force Mains ............................................................... 17 9.7 Backfill and Compaction ............................................................................................... 18 10 Recommendations for Further Investigations ..................................................................... 19 11 Closure ....................................................................................................................................... 19 12 References ................................................................................................................................. 20 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 iii CO N T E N T S Exhibits Exhibit 6-1: Groundwater Measurements as of September 10, 2024 ............................................8 Exhibit 7-1: Seismic Design Parameters, Site Class D ...................................................................10 Exhibit 8-1: Slope Stability Model Results Summary ....................................................................11 Exhibit 9-1: Nominal Pin Pile Capacities Following SDCI Director's Rule 10-2009 .................14 Figures Figure 1: Vicinity Map Figure 2: Site Key Plan Figure 3: Site Plan (8 Sheets) Figure 4: Geology Figure 5: Historical Contours and Shoreline Appendices Appendix A: Boring Logs Appendix B: Laboratory Test Results Appendix C: Existing Information by Others Appendix D: Slope Stability Analysis Results Important Information Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 iv AC R O N Y M S ACRONYMS AASHTO Association of State Highway and Transportation Officials ASCE American Society of Civil Engineers bgs below ground surface bpf blows per foot FS factor of safety H:V Horizontal to Vertical HDD Horizontal Directional Drilling OD outside diameter pcf pounds per cubic foot PGA peak ground acceleration psf pounds per square feet SPT Standard Penetration Test USCS Unified Soil Classification System VWP vibrating wire piezometer WSDOT Washington State Department of Transportation Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 1 1 INTRODUCTION The purpose of this project was to conduct geotechnical explorations and provide engineering recommendations to support the design of the proposed Kennydale Lakeline Sewer Improvements Project (project) located in Renton, Washington. To accomplish this, Shannon & Wilson advanced five geotechnical borings in the project area and reviewed existing geotechnical data along the proposed sewer alignment. Soil samples recovered from the borings were tested in our geotechnical laboratory in Seattle, Washington. Presented in this report are a site and project description, a description of our geotechnical investigation, interpretation of subsurface conditions, laboratory testing results, and conclusions and recommendations from our engineering studies based on the results of subsurface geotechnical explorations. This report is intended for use by the project design engineering staff, Carollo Engineers, Inc., the City of Renton, and their representatives. 2 SITE AND PROJECT DESCRIPTION The existing Kennydale Lakeline Sewer System is located within the City of Renton, Washington, and primarily lies in Lake Washington, as shown in Figure 1, Vicinity Map. The project generally begins near Lake Washington Boulevard and North 38th Street on the north end and terminates along Mountain View Avenue North near North 29th Street. An overview of the project area is shown in Figure 2. A site plan depicting the existing lakeline, site features, and the locations of our explorations are shown in Figure 3, Sheets 1 through 8. The topography of the area is generally sloping downward from east to west toward the Lake Washington shoreline. The area is developed with residential houses that are accessed by a paved access road. Vegetation in the area generally consists of landscaping, including grass and trees. The east rail trail parallels the project and, in most areas, has a vegetated buffer on either side of the trail that consists of grasses, bushes, and trees. Centrally located along the alignment is Kennydale Beach Park, which includes a man-made beach area that is retained by a bulkhead structure. The existing lakeline sewer system was constructed in 1972 to provide sanitary sewer service to the lakefront homes along Lake Washington from the north end of Coulon Beach Park to the southerly end of what was Barbee Mill. This project is intended to replace that system with a system upland from the residences along the lake. The new system generally consists of individual lift stations that will pump the sewage to new lateral connections on the upland side of the residences. The laterals will then connect to a low pressure force main Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 2 that generally parallels the shoreline upland of the residences and discharges to the City of Renton gravity wastewater system. This facility provides sanitary sewer service to approximately 55 single-family homes along the lakefront. To support this system, a new 50kva generator is proposed along Burnett Avenue North, to provide electricity to the system. 2.1 Geologic Setting The project is located in the central portion of the Puget Lowland, which is an elongated, north-south depression situated between the Olympic Mountains and the Cascade Range. Repeated continental glaciations (glacial events) in this region strongly influenced present- day topography and geology. The area has been glaciated six or more times in the past two million years. Each glacial advance sculpted the terrain by depositing new sediment and partially eroding previous sediment. During the last glacial advance, known as the Vashon, the weight of the glacial ice compacted and overconsolidated the underlying soil. Soil deposited prior to or by the advancing glacier is typically dense to very dense or very stiff to hard. Soil deposited as the glacial ice receded or after the last glacial ice retreated, approximately 16,500 years ago, is normally consolidated (Porter and Swanson, 1998; Booth and others, 2003). Normally consolidated deposits are typically loose to medium dense or soft to stiff. Humans altered the landscape in the project area over the past 150 years. The completion of the Lake Washington Ship Canal lowered Lake Washington by 8.8 feet in 1916, exposing beach, peat, and lacustrine deposits around the lake margins (Chrzastowski, 1983). Tectonically, the Puget Lowland is located in the forearc of the Cascadia Subduction Zone. The tectonics and seismicity of the region are the result of the relative northeastward subduction of the Juan de Fuca Plate beneath the North American Plate. North-south compression is accommodated beneath the Puget Lowland by a series of west- and northwest-trending faults that extend to depths of about 12 miles. The nearest active fault to the project is the Seattle Fault, which consists of a series of four or more east-west-trending, south-dipping fault splays beneath Seattle and the vicinity. The fault is located about 3 to 4 miles north of the project area. It extends from Bremerton to the Snoqualmie River Valley, along an alignment that is roughly coincident with and south of Interstate 90. In addition to strong shaking, local seismicity poses other hazards to the project area, including landslides, seiches, and landslide-generated tsunamis. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 3 2.2 Holocene Deposits Normally consolidated Holocene deposits mantle most of the terrain in the Puget Lowland, including in the project area. Nonglacial processes, which largely continue today, deposited these sediments. These include erosion, landsliding, stream action, organic accumulation, and human activities such as regrading and filling. Holocene deposits have not been glacially consolidated, and as a result they tend to have densities in the very loose to medium dense or very soft to stiff range. Local Holocene deposits include the following: Peat (Hp) – Depression fillings of organic soils, including peat, peaty silt, and organic silt; typically very soft to medium stiff. Lacustrine (lake) Deposits (Hl) – Depression fillings of fine-grained soils, including silt, clayey silt, and silty clay; commonly with scattered organics. Typically very soft to stiff or very loose to medium dense. Beach Deposits (Hb) – Deposits along present and former shorelines of Lake Washington. Typically, loose to medium dense sands and gravels; includes organics, wood, and shells. Fill (Hf) – Materials placed by humans, both engineered and nonengineered. Typically, very loose to very dense, comprised of various materials including soil, cobbles, and wood chips and debris. 2.3 Vashon Glacial Deposits Vashon glacial deposits include normally consolidated sediment that accumulated during the recession of the Vashon ice sheet, and glacially consolidated sediment that was overridden by an ice sheet. 2.3.1 Vashon Recessional Glacial Deposits Vashon recessional glacial deposits accumulated during retreat or wasting of the most recent glacial ice incursion. The base of the recessional units coincides with the top of glacially overridden soils. Recessional units observed in the project vicinity include recessional outwash (Qgo in Figure 4) and recessional lacustrine deposits. Recessional outwash deposits are glaciofluvial sediments that typically consist of clean to silty sand, gravelly sand and sandy gravel. Cobbles and boulders are common. These deposits are typically loose to very dense. 2.3.2 Glacially Overridden Vashon Glacial Deposits Glacially overridden Vashon glacial units observed in the project area include glacial till (Qgt in Figure 4). Glacial till accumulated during the Vashon ice sheet directly under the Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 4 Vashon ice sheet. It generally consists of gravelly silty sand and silty gravelly sand, with some clay. Cobbles and boulders are common. Glacial till is typically very dense. 2.3.3 Glacially Overridden Pre-Vashon Deposits Soils deposited prior to the Vashon glaciation, and subsequently overridden, are present at and near the surface in the project area. These soils are generally grouped together in the available existing maps and data as Pleistocene-era continental glacial drift and include glacially-derived and non-glacial deposits (Qgpc in Figure 4). Because the soils were glacially overridden, they are typically very dense or very stiff to hard. 3 SUBSURFACE EXPLORATIONS Subsurface explorations consisted of advancing and sampling five borings at the site between August 28 and 30, 2024. Approximate boring locations are shown in the site plan included as Figure 3. The boring locations were selected by the project team based on publicly accessible areas along the alignment and to provide relatively even coverage of the project area. Locations were adjusted in the field to avoid utility conflicts. The boring locations, shown in Figure 3, were positioned based on proximity to observable site features. Elevations shown in the boring logs were estimated based on the 5-foot contour maps available through the King County iMap site (2024). Therefore, the boring locations and elevations shown in the site plan and boring logs should be considered approximate. The borings, designated Borings B-1 through B-5, were advanced to depths ranging from 15.5 to 25.9 feet below the ground surface (bgs) to evaluate the subsurface conditions along the proposed sewer alignment, and in the vicinity of the proposed generator. Drilling services for this project were provided by Geologic Drill Partners of Fall City, Washington, using a track-mounted, Acker Recon drill rig and a Bobcat mounted MT55 drill rig. A Shannon & Wilson representative was present during drilling to locate the borings, observe drill action, collect samples, log subsurface conditions, and observe groundwater conditions. We coordinated with the Washington Utility Call Center and contracted with Applied Professional Services to clear the boring locations of buried private and public utilities prior to drilling. The borings were advanced with 6.5-inch-outer-diameter (OD), continuous flight, hollow- stem augers to depths ranging from approximately 15.5 to 25.9 feet bgs. As the borings were advanced, samples were generally recovered using the Standard Penetration Test (SPT) method at 2.5-foot intervals to 20 feet bgs (or to the bottom of the boring if shallower than 20 feet) and then at 5-foot intervals to the bottom of the boring. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 5 In the SPT method, samples are recovered by driving a 2-inch-OD split-spoon sampler into the bottom of the advancing hole with blows of a 140-pound hammer free falling 30 inches onto the drill rod. For each sample, the number of blows required to drive the sampler the final 12 inches of an 18-inch penetration into undisturbed soil is recorded. Where the sampler did not penetrate the full 18 inches, our logs report the blow count and corresponding penetration in inches. Blow counts are shown graphically in the test hole log figures as “penetration resistance” and are displayed adjacent to sample depth. The penetration resistance values give a measure of the relative density (compactness) or consistency (stiffness) of cohesionless or cohesive soils, respectively. The soil samples recovered during drilling were observed and described in the field in general accordance with the classification system described by ASTM D2488. Selected samples recovered during drilling were tested in our laboratory to refine our soil descriptions in general accordance with the Unified Soil Classification System (USCS) described in Appendix A. After drilling, all geotechnical borings were completed with vibrating wire piezometers (VWPs) and then backfilled with bentonite chips to just below the ground surface. The VWPs were connected to dataloggers, which were installed in flush-mounted well monuments set in concrete. 4 LABORATORY TESTING Laboratory tests were performed on selected samples recovered from the borings to confirm field descriptions and to estimate the index properties of the typical materials encountered. The index testing was formulated with emphasis on estimating the material gradation, in situ water content, plasticity characteristics, resistivity, and pH. A summary table of laboratory test results is presented in Appendix B. Water content tests were performed on the samples returned to our laboratory. The tests were performed in general accordance with ASTM D2216. The results of the water content measurements are presented graphically in the boring logs in Appendix A. Grain-size classification (gradation) testing was performed to estimate the particle-size distribution of selected samples from the borings. The gradation testing generally followed the procedures described in ASTM C117/C136 and D422. The test results are presented in Appendix B, and summarized in the boring logs as percent gravel, percent sand, and percent fines. Percent fines in the boring logs are equal to the sum of the silt and clay fractions indicated by the percent passing the No. 200 sieve. Note that hydrometer testing indicates particle size only, and visual classification under USCS designates the entire Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 6 fraction of soil finer than the No. 200 sieve as silt. Plasticity characteristics (Atterberg Limits results) are required to differentiate between silt and clay soils under USCS. Atterberg Limits were evaluated for four samples of cohesive/fine-grained soil recovered during drilling to estimate plasticity characteristics. The tests generally followed procedures described in ASTM D4318. The results are presented in Appendix B and in the boring logs in Appendix A. Nine selected samples were tested for soil resistivity, in general accordance with American Association of State Highway and Transportation Officials (AASHTO) T288, and for pH to assist in determining the corrosion potential of site soils. The results of resistivity testing are shown in the boring logs in Appendix A. 5 EXISTING DATA REVIEW Existing geotechnical data was reviewed from within the project area to support our understanding of the subsurface conditions. Borings from two residences along Lake Washington were reviewed: 3111 Mountain View Avenue North and 3307 Mountain View Avenue North. The following reports and the associated boring and test pit logs are included in Appendix C: Geotechnical Engineering Study, Proposed New Napoli Residence 3111 Mountain View Avenue North, Renton, Washington. Geotech Consultants, Inc., November 2017. Geotechnical Engineering Study, Proposed New Residence 3307 Mountain View Avenue North, Renton, Washington. Geotech Consultants, Inc., March 2020. In addition to historical subsurface data, historical topographic sheets (T Sheets) were obtained from the Puget Sound River History Project, a project of the University of Washington’s Department of Earth and Space Sciences. The historical T Sheets were developed in 1902 by the U.S. Coast and Geodetic Survey and show the native historical shoreline along Lake Washington. The T-Sheet is shown overlain on recent aerial imagery in Figure 5. Based on review of these materials, borings advanced as part of this project were generally advanced on or inland of the historical Lake Washington shoreline. Changes in the shoreline near the project site can be attributed to the lowering of the water level in Lake Washington following the completion of the Lake Washington Ship Canal. Additional shoreline changes may be due to fill, placed to expand development into Lake Washington. The report for the residence at 3111 Mountain View Avenue North is likely located on historical upland area. Two soil borings, designated Borings 1 and 2, were advanced to Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 7 between 16.5 and 26.5 feet bgs. Boring 1 encountered approximately 8 feet of dense silty sand overlying dense to very dense sand to a depth of 26.5 feet. Boring 2 encountered dense to very dense silty sand with gravel from the ground surface to 16.5 feet bgs. Groundwater was not encountered in either boring at the time of drilling. A note in the log for Boring 1 indicated the soil became wet at 20 feet bgs and may be associated with the seasonal water table. The report for the residence at 3307 Mountain View Avenue North is likely located within the historical Lake Washington footprint. Two test pits, designated Test Pits 1 and 2, were excavated to between 3.5 and 4.5 feet bgs. Test Pit 1 encountered loose slightly gravelly silty sand that was noted as fill to 2 feet bgs overlying loose, slightly silty sand to 4 feet bgs. The test pit terminated in dense silty sand at 4.5 feet bgs. Water was noted seeping into the test pit between 2 and 4 feet bgs. Test Pit 2 encountered loose slightly gravelly silty sand that was noted as fill to 2 feet bgs overlying dense silty sand to the bottom of the test pit at 3.5 feet bgs. Groundwater seepage was not observed in Test Pit 2. It is likely that the dense soils encountered in the test pits and borings are native soils. Based on their dense to very dense nature, the soils are likely glacially consolidated deposits. 6 SUBSURFACE CONDITIONS The subsurface soil and groundwater conditions encountered in our explorations are presented graphically in the boring logs in Appendix A. Borings B-2, B-3, and B-4 encountered asphalt pavement at the ground surface between 2 and 8 inches thick. Near surface soil deposits were highly variable, but in all cases were overlying glacial till encountered deeper in the soil profile. Borings B-1 and B-5, located on opposite ends of the project, each encountered glacial till soils consisting of very dense silty sand from the ground surface to the bottom of the boring at approximately 15 feet. In Boring B-5, the till soil at the base of the boring became predominantly fine-grained, sandy silt. Boring B-2, located adjacent to Kennydale Beach Park and nearest to Lake Washington, encountered fill consisting of sand with silt and gravel from the base of the asphalt to 3 feet bgs. The clean layer consistent with structural fill was underlain by clayey sand with gravel to 4.5 feet bgs. Glacial till consisting of very dense silty sand was encountered at 4.5 feet bgs to the bottom of the boring at 16.5 feet bgs. Boring B-3, located higher in elevation and furthest from Lake Washington, encountered alternating layers of Vashon Recessional Lake deposits and Vashon Recessional Outwash Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 8 deposits. The lake deposits generally consisted of lean clay with variable amounts of sand. The outwash deposits generally consisted of sand with silt to silty sand. Both the lake and outwash deposits are likely normally consolidated based on penetration resistance values of 5 to 10 blows per foot (bpf). The alternating sequence of recessional deposits terminated at 25 feet bgs where glacial till was encountered. Boring B-4 encountered Vashon Recessional Outwash deposits consisting of silty sand to 7 feet bgs. The outwash was underlain by glacial till to 14 feet bgs. The till was underlain by glacially overridden alluvial deposits to the bottom of the boring at 15.9 feet bgs. Based on the results of laboratory testing, fines content in the till soils was generally between 32% and 62%. Moisture contents were generally between 8% and 11%. Resistivity values in the till soils range from 2200 to 8900-ohm centimeters and pH values were between 7.2 and 8.6. Based on the results of laboratory testing, moisture contents in the recessional outwash deposits were generally between 12% and 20%. Measured soil resistivity in the sample tested was 4800-ohm centimeters and the pH value was 7.2. Based on the results of laboratory testing, moisture contents in the recessional lake deposit were generally between 20% and 23%. Measured soil resistivity in the sample tested was 4100-ohm centimeters and the pH value was 8. Groundwater was encountered during drilling in Borings B-2 through B-5 between 3 and 15.9 feet bgs. VWP readings are being collected on an hourly basis. Data from the datalogger is downloaded approximately every two months. Based on VWP readings to date, the highest observed groundwater surface in each boring is summarized in the Exhibit 6-1. Exhibit 6-1: Groundwater Measurements as of September 10, 2024 Boring ID Depth Below Ground Surface (Feet) Date of Reading B-1 3.6 9/4/24 B-2 3.1 9/3/24 B-3 14.6 9/3/24 B-4 15.9* 8/29/24 B-5 5.33 9/6/24 NOTE: * Water not shown on piezometer to date; reading is from time of drilling. Note that water levels may fluctuate by several feet seasonally and may vary during periods of high precipitation. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 9 7 SEISMIC CONDITIONS Washington experiences more than 1,000 earthquakes per year (Washington Emergency Management Division, 2023). The Puget Sound region is historically subjected to both small and large earthquakes. The tectonics and seismicity of northern Puget Sound are largely the result of its location in the Cascadia Subduction Zone, which extends from Northern California to southern British Columbia. In the Puget Sound, this zone sees the Juan de Fuca Plate moving eastward, subducting under the North American Plate (U.S. Geological Survey, n.d.). Active seismicity in the Puget Sound region generally occurs as both deep earthquakes associated with the subduction zone (inter- and intraplate events), as well as shallow earthquakes associated with crustal faulting in the North American Plate. Each source may cause significant ground shaking at the site over the life of the project. The design of the project will need to consider these factors and the potential effects (e.g., peak ground acceleration [PGA], lateral spreading, etc.) that seismic activity could have on the structure foundations. 7.1 Seismic Design We understand that a generator is included as part of the improvements and that it will need to be designed to meet seismic code. The seismic design for the project was determined in general accordance with the 2021 International Building Code (International Code Council, 2020) and American Society of Civil Engineers (ASCE) 7-16, Minimum Design Loads for Buildings and Other Structures (ASCE, 2017). Based on the subsurface conditions encountered in our explorations at the site and engineering judgment, the site class (Boring B-3), according to ASCE 7-16, is Site Class D based on an average penetration resistance in the upper 100 feet of the soil column of greater than 15 bpf. It is our understanding the project structure (generator) will have a fundamental period less than 0.5 second; therefore, the spectral acceleration values can be determined based on Site Class D. For the project site, Site Class D also requires site response analysis unless the exceptions in Section 11.4.8 of ASCE 7-16 (2017) are met. Exhibit 6-1 provides recommended spectral acceleration response parameters assuming the exceptions are taken. A site-specific response analysis has not been performed. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 10 Exhibit 7-1: Seismic Design Parameters, Site Class D Seismic Design Parameters (Site Class E) Value Source Acceleration Coefficient, (PGA) 0.619 (g) ASCE 7-16 Hazard Tool Spectral Acceleration Coefficient at Period of 0.2s, (Ss) 1.45 (g) ASCE 7-16 Hazard Tool Spectral Acceleration Coefficient at Period of 1.0s, (S1) 0. 50 (g) ASCE 7-16 Hazard Tool Site Factor at Zero Period, (Fpga) 1.1 ASCE 7-16 Table 11.8-1 Site Factor for Short Period, (Fa) 1.0 ASCE 7-16 Table 11.4-1 Site Factor for Long Period, (Fv) 1.8 ASCE 7-16 Table 11.4-2 7.2 Liquefaction Potential Liquefaction potential for the project was assessed based on soil and groundwater observations. Liquefaction may occur near the ground surface in recessional outwash deposits or uncompacted fill deposits. In most cases, groundwater appears to be perched above the glacially overridden soils; liquefaction, if it occurs, will likely affect a relatively thin layer of soil. Groundwater was not encountered in the loose, or medium stiff soils encountered at B-3 where the generator pad will be founded; therefore, liquefaction is not anticipated at the generator site. 8 SLOPE STABILITY ANALYSIS Slope stability analysis was conducted for the generator site, which is located in a parking lot adjacent to a slope which slopes down to the west toward Lake Washington Boulevard. Modeling was performed using Slope/W software, by Bentley Systems, Inc. (version 2024.1). The software uses limit equilibrium analysis to solve for the minimum factor of safety (FS). Several analysis methods are available; for this model, the Morgenstern-Price method was selected. The purpose of this modeling is to evaluate the need for a retaining structure to support the proposed generator foundation. Slope modeling was based on existing slope contours provided on the King County iMap site (2024). Contour intervals are 5 feet, and the model geometry should be considered approximate. The modeling location was determined based on plan set sheet ES07 provided by Carollo Engineers and dated May 2022. This sheet shows the location of the generator at the far north end of the existing parking area on Burnett Street. Based on the iMap contours, the slope in the area of the generator is approximately 10 feet tall, with a slope angle of approximately 1.6 Horizontal to 1 Vertical (1.6H:1V). Based on the contours, the generator location is approximately 5 feet lower in elevation than the location Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 11 of Boring B-3. The soil stratigraphy was assumed to be horizontal between sites and was adjusted for the difference in elevation. Soil properties used for the modeling are presented in Appendix D. Three scenarios were selected for the modeling, which considered different drainage and seismic conditions: Static analysis assuming undrained loading. Static analysis assuming long term drained loading. Pseudo-static (seismic) analysis assuming undrained loading. Pseudo-static analysis was conducted using a horizontal acceleration of 0.5 times the peak ground acceleration, or 0.34 times the acceleration of gravity (g). Modeling of groundwater and surface water was conducted using an assumed piezometric water surface and did not include seepage effects or effects of pore pressure generation. A surcharge load of 500 pounds per square foot (psf) was added to the top of the slope to account for the generator improvements, and nearby vehicle traffic loading. The results of the modeling are shown in Appendix C and are presented in Exhibit 7-1. Based on these results, static loading using long-term drained soil properties is not stable. Exhibit 8-1: Slope Stability Model Results Summary Loading Scenario Model Factor of Safety Static, undrained Morgenstern-Price 2.2 Static, drained Morgenstern-Price 0.8 Pseudo-static, undrained Morgenstern-Price 1.6 Note, the results of the stability analysis are strongly influenced by the slope geometry. More reliable results may be obtained after completion of surveying in the area of the generator. 9 GEOTECHNICAL RECOMMENDATIONS The recommendations contained in this report are based on the results of our subsurface explorations, and review of existing geotechnical information in the project area. In general, our explorations encountered variable thickness of recessional deposits or fill, overlying glacial till. The thickness of recessional deposits and fill across the project site are variable and range from till soils at the ground surface to recessional deposits on the order of 25 feet Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 12 thick. We believe these soils are acceptable for achieving a well-constructed project, provided the recommendations described herein are followed. We understand that recommendations are needed for bearing capacity for the ILS grinder pumps, and the generator. Slope stabilization is also necessary below the generator. A fill- type retaining wall was assumed to be necessary at the time of proposal. We understand that additional area for the generator is not required with the current generator placement, and a wall may no longer be necessary. Additional recommendations are necessary for excavation and open trenching for the installation of the ILS grinder pumps and the sewer laterals and main. Trenching will likely encounter groundwater in some areas; recommendations are provided to address groundwater concerns. 9.1 ILS Foundations We understand that the ILS grinder pumps will bear on a concrete foundation block, which will support the grinder pump and provide uplift resistance to counteract buoyancy forces on the pump. We understand that the pump manufacturer has recently developed a new pump that may resist buoyancy via side friction. Based on the shallow groundwater in areas at the site, the presence of medium dense recessional outwash deposits, and the potential for liquefaction during a seismic event, we recommend resisting uplift using dead weight, and do not recommend relying on side friction. We understand the base of the grinder pump will be embedded a minimum of 5 feet bgs. The grinder pump locations are generally west of our explorations, and nearer to Lake Washington. Based on the available data, it is likely the pumps will bear on glacial till, or recessional outwash deposits. We assume that the foundation will have a minimum dimension of 30 inches. The ILS foundations should be constructed on dense, unyielding native soils. The base of excavations for the ILS foundations will likely be below the existing groundwater table. Water will need to be prevented from pooling in the bottom of the excavation. Excavations near finish grade should be conducted with flat-nosed bucket, if possible, to limit disturbance to the silty native soils. If loose soils are encountered at the base of the excavation, they should be removed and replaced with Washington State Department of Transportation (WSDOT) M41-10 Gravel Borrow, placed and compacted to a dense and unyielding state, as described in Section 9.7. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 13 9.1.1 Bearing Capacity Foundations constructed as described above may be designed for an allowable vertical bearing capacity of 3,000 psf. For load combinations, including wind and earthquake loading, this allowable bearing capacity may be increased by 33%. This allowable bearing capacity assumes that foundations are vertically loaded, constructed with a horizontal base, and bear on horizontal soil surfaces. 9.1.2 Settlement We estimate settlements of an isolated foundation will be less than ½ inch. These settlements are expected to occur as the structural loads are applied due to the relatively granular nature of the soil. Differential settlements are not anticipated, given the relatively small dimensions of the foundation block and the significant lateral support due to the burial depth. 9.2 Generator Foundation We understand the generator will be installed on a concrete pad in the northwest corner of the existing parking area off of Burnett Avenue North. The site soils consist of approximately 15 to 20 feet of alternating recessional outwash and recessional lake deposits. The recessional lake deposits consist primarily of clay soils and are typically medium stiff to stiff. Undisturbed samples were not obtained during our explorations and consolidation testing was not performed. These soils may be prone to settlement with additional loading. In order to limit the potential for total and differential settlements for the generator, we recommend that the generator pad be supported by pin piles, which will transfer the loading to deeper, less settlement sensitive bearing strata. The pin pile foundation elements should be connected by a pile cap grade beam or mat, which in turn supports the above grade generator. Pin piles typically consist of Schedule 40 (3- to 6-inch piles) or Schedule 80 (2-inch piles) steel pipe sections. Piles are comprised of one or more pipe sections joined by internal friction couplers or welding. Piles should be designed to consider corrosion of the pile material. Protective coating, such as galvanizing or epoxy, should be provided to limit corrosion during the service life of the piles. Pin pile driving is completed using a pneumatic or hydraulic impact hammer ranging in weight class from 90 to 5,000 pounds. Pin piles should be driven with an impact hammer selected by the Contractor to be appropriate for the size of pin pile used, site access conditions, and required pin pile capacity. The Contractor should provide a final driving Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 14 rate for their chosen combination hammer, pile size, and design capacity. All piles should be driven such that the same final driving rate is met. We anticipate that penetration depths of at least 20 feet below the existing ground surface will be required to achieve an acceptable pile capacity. Pile testing should be completed in accordance with the ASTM D1143-81 “quick load test” procedure. If testing indicates insufficient pile capacity, the final driving rate should be revised and all piles re-driven to meet the revised criteria. Pile capacity should be verified by testing approximately 3% of the installed piles (maximum of five, minimum of one) in vertical compressive loading to twice the design capacity. Pile capacity for design should depend on the size of the pile as described in Seattle Department of Construction and Inspections (SDCI) Director’s Rule 10-2009, reproduced in Exhibit 9-1. We anticipate that 2- or 3-inch-diameter pin piles will be appropriate for this project. Exhibit 9-1: Nominal Pin Pile Capacities Following SDCI Director's Rule 10-2009 (SDCI, 2009) Nominal Pile Diameter Design Vertical Capacity 2-inch 3 tons 3-inch 6 tons 4-inch 10 tons 6-inch 15 tons NOTES: One ton = 2,000 U.S. pounds. Nominal pile sizes may not match measured pile diameter. We recommend that the Shannon & Wilson be retained to observe pin pile installation and testing on a full-time basis. Full-time observation will allow us to verify that pin pile installation is completed in accordance with the project plans, specifications, and our recommendations, in addition to timely resolution of installation and performance issues. 9.3 Slope Stabilization We conducted slope stability analysis (Section 8.0) to evaluate the stability of the existing slope below the proposed generator location. Based on this analysis, the existing slope may be unstable under long-term static conditions, if drained conditions develop. The results of our slope stability analysis are presented in Appendix D. At the time of our proposal, it was assumed that a fill-type wall would be required to create space for the generator pad at the top of the slope and to stabilize the slope. We understand that the current positioning of the generator pad does not require additional space at the top Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 15 of the slope; therefore, we recommend reinforcing the existing slope to provide the needed stabilization. Slope stabilization was analyzed using soil nails to provide passive resistance to the slope face. Nails were modeled assuming a 20-foot embedment length and 5-foot horizontal spacing along the slope, and using four evenly spaced rows of nails in the vertical direction (approximately 3.5-foot spacing). We have assumed nails will be installed at 10 degrees below horizontal. We assumed an anchor bond diameter of 2.5 inches and an allowable bond strength of 3 pounds per square inch (includes an FS of 2 against pullout). Our preliminary analysis is included in Appendix D. Several anchor options are available that could provide the needed pullout capacity, including the following: Spiral nails Grouted soil nails Helical anchors Due to the relatively low capacity requirements, the relative speed of installation, and the decreased disturbance to the existing clay soils, our preferred anchor option would be the spiral nail system. A spiral nail system was assumed in our analysis. Note, the soils encountered in our boring were generally loose to medium dense or medium stiff to stiff, however, the soils are glacially derived and may contain cobbles or boulders not encountered in our explorations. The Contractor should be prepared to address obstructions if encountered. The spiral nail system uses a twisted (spiraled) square bar that is twisted into the slope to provide reinforcement. The nail is then locked off to a “spider,” which consists of eight "legs" of steel bar that spread out and transfer the soil nail load to the surrounding ground. After completion, the slope can be revegetated to match the existing appearance. Additional facing options are available to match the desired aesthetic. In general, final design of this type of slope stabilization would be designed by the Contractor and the soil nail system manufacturer. Our assumed preliminary design should be re-evaluated once survey has been completed at the site to confirm our analysis. 9.4 ILS Excavation and Temporary Shoring We understand that the ILS structures will require excavations between 5 and 10 feet bgs. The ILS structures are relatively small (approximately 2.5-foot-diameter basin) and would be located adjacent to each residence, in the lowest parts of the residential lots, in order to connect to the ground or basement levels of the existing homes. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 16 We anticipate that the ILS excavations will be made using conventional excavating equipment, such as rubber-tired backhoes or tracked hydraulic excavators, or with vactor excavation methods where access is limited. Soils within the excavation areas are likely to consist of fill, or native soils consisting of normally consolidated recessional deposits including silts, silty sands, and sands that may contain gravel. Clay soils were not generally encountered in our explorations along the sewer alignment, but were encountered in Boring B-3 and may exist near ILS excavations. Glacial till soils were encountered in our explorations underlying recessional deposits and as shallow as the ground surface. Glacial till encountered in the excavations, may require ripper teeth on the excavating bucket or a hoe ram to facilitate excavation. In addition, based on our experience, boulders and other obstructions may be encountered in fill and native soils in the project area, and the Contractor should anticipate their presence. It is our understanding that the design of the temporary shoring system and the method of construction will be the responsibility of the Contractor, as is the standard of practice in the Project area. If the excavations extend below the groundwater table, which is expected in many areas based on the level of Lake Washington and groundwater encountered in our explorations, some form of groundwater control will be required. The design and implementation of the groundwater control system should be compatible with the selected shoring system. Conceptually, the overall shoring and groundwater control system may include some form of relatively watertight shoring in upper non-glacial soils to provide both excavation support and water control. Driven systems, such as sheetpile walls, are unlikely to be driveable into very dense glacially consolidated soils. Glacially overridden soils, such as glacial till, are unlikely to transmit significant groundwater flow over a relatively short excavation duration and may be competent enough to stand unsupported by shoring. 9.5 Sewer Main and Lateral Excavation and Temporary Shoring The sewer main excavation in the roadway and lateral excavations through driveways and landscaped areas are likely to encounter fill soils, recessional deposits, and glacial till soils. Recessional soils typically consist of normally consolidated silts, silty sands, and sands that may contain gravel. Clay soils were not encountered in our explorations along the sewer alignment, but were encountered in Boring B-3 and may exist in other locations along the sewer alignment. Till soils are likely to consist of very dense silty sands with or without gravel, cobbles, and boulders. We anticipate that trench excavations for the sewer main could be made using conventional excavating equipment, such as rubber-tired backhoes or tracked hydraulic excavators. As described above, the dense to very dense till soils may require ripper teeth on the excavating bucket or a hoe ram to facilitate excavation, and boulders and other obstructions may be encountered in the fill and till deposits. We anticipate that the sewer main trench excavations will be shored using trench boxes with Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 17 temporary construction dewatering, as required, to lower the groundwater to about 2 feet below the base of the excavations. We understand excavation depths will typically be shallow, on the order of 3 feet bgs. Groundwater was observed as shallow as approximately 3 feet in our borings, therefore groundwater may be encountered during construction. Where excavations will extend into the groundwater table, we recommend designing a construction dewatering plan which may include sumps and pumps, well points, and/or cutoff trenches to intercept groundwater from entering the excavation area. The effectiveness of the various methods will depend on the hydraulic properties of the excavated soils at the site. If the soil to be excavated has a low hydraulic conductivity, and is left open for a short amount of time, small amounts of seepage may be addressed with sumps and pumps from the base of the excavation. If hydraulic conductivity is relatively high, dewatering with well points may be appropriate to draw down the water table in the vicinity of the excavation. In areas of steeper relief, where water seepage is high, and from a dominant direction, cutoff trenches may be excavated uphill of the sewer trench to intercept water. Water may be pumped from the cutoff trench and around the excavation location. 9.6 Trenchless Alternative for ILS Force Mains As part of the overall system, small diameter force mains would be installed from the ILS to the sewer main in the roadway. We understand that use of a trenchless method is being considered to limit surface disturbance if it is determined to be feasible. Note that in general, even if feasible, trenchless construction has inherently greater risks and uncertainty than typical construction of open cut pipeline. Based on geotechnical data these alignments would likely be in some combination of loose/soft Holocene deposits and dense to very dense glacially-derived soils, including glacial till and recessional outwash. Horizontal Directional Drilling (HDD) in particular can accommodate these ground conditions, with some risks. One risk includes encountering cobbles or boulders, particularly in the till, but also in the outwash or fill soils. In such a case, the HDD may need to be steered around such an obstruction. HDD hole stability is also a concern, although less so in till soils and with the anticipated small diameter (4 inches or less) of these bores. Advancement of the HDD along subsurface soil contacts (such as between till and outwash deposits or Holocene and glacial deposits) may be difficult to control, and grades may be difficult to maintain. An additional risk is borehole stability. Since outwash is less self-supporting than till, the stability of the borehole will need to be more closely monitored where outwash is encountered. Where borehole stability is an issue, drilling mud must be maintained in the Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 18 bore during drilling, reaming and pipe pullback. If drilling mud cannot be maintained in the bore, the soils may squeeze or collapse into the bore and the cohesionless soils beneath the groundwater table could flow into and collapse the bore, resulting in ground losses, potential sinkholes, and the inability to install the pipe. Inadvertent fluid release or “frac outs,” may also occur when slurry pressure in excess of the total allowable stress in the ground is applied to the walls of the HDD bore. Fractures in the soil can conduct slurry into the environment surrounding the bore. Fractures extending upward toward the ground surface may result in a release of slurry to the ground surface (inadvertent drilling fluid or slurry release). An analysis of frac out is beyond the scope of the current effort, but note that inadvertent drilling fluid or slurry release should be anticipated even with the best of designs and experience. Due to the relatively shallow burial depth of the laterals, we believe frac outs may be likely. We recommend that the Contractor provide a contingency action plan for remediation should an event occur. The plan should include methods for identifying when an event has occurred, who needs to be notified and when, and what will be the immediate action by the Contractor to control the event. Long-term cleanup, if necessary, will depend on the nature of the event and can be decided at a later time based on site-specific situations. We understand that other issues, such as staging areas, drill direction, and trenchless methods, are being addressed by another consultant. 9.7 Backfill and Compaction Structural fill will be required across the site, including around ILS grinder pumps, under asphalt and concrete pavements, and beneath concrete pads. Structural fill that is placed should be clean, well-graded, granular soil to provide drainage and frost protection. Select Borrow and Gravel Borrow, as defined by the WSDOT M41-10, meets these requirements and can typically be placed in both wet and dry conditions. Bedding material will be necessary around sewer mains and laterals. Bedding material should consist of WSDOT M41-10 Gravel Backfill for Pipe Zone Bedding. Structural fills beneath footings, and pavement structural sections should be placed in lifts not to exceed 12 inches loose thickness and compacted to 95% of the maximum density as determined by the Modified Proctor compaction procedure (ASTM D1557). When backfilling within 18 inches of ILS grinder pumps, material shall be placed in layers not to exceed 6 inches loose thickness and densely compacted with hand-operated equipment. Heavy equipment shall not be used, as it could damage the pumps. During fill placement, we recommend that large cobbles or boulders with dimensions in excess of 4 inches be removed from structural fills. In addition, care should be taken during fill placement to Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 19 ensure that they are not “contaminated” with deleterious matter, such as organics, frozen soils, etc. Pipe bedding should be placed in lifts not exceeding 4 inches if compacted with hand-operated equipment, or 8 inches if compacted with heavy equipment. Each lift should be compacted to a dense, unyielding condition and to at least 92% of the maximum dry density (ASTM D1557) 18 inches or more below the pavement subgrade, and 95% within 18 inches of the pavement subgrade. We recommend a minimum cover over utilities of 2 feet from the crown of the pipes or conduits to the top of the pavement subgrade. In landscaped areas, less compaction is required, and material may be placed in thicker lifts (up to 18 inches) and moderately compacted to achieve at least 90% compaction. The existing surficial site soils likely to be encountered in site excavations are generally high in fines and are not suitable for reuse in areas requiring structural fill or pipe bedding. Non-structural fills, such as those placed above the pipe bedding in landscaped areas may be reused provided they are free of deleterious matter, such as organic and highly plastic soils. If the existing soil is not suitable for reuse, we recommend backfilling with fill that meets the requirements of WSDOT M41-10 Common Borrow Option A or B. Non-structural fills should be placed in similar lifts and compacted to at least 90% of the Modified Proctor maximum density. We recommend that our services be retained to inspect the quality of fill compaction during construction. 10 RECOMMENDATIONS FOR FURTHER INVESTIGATIONS Subsurface conditions adjacent to the residences where the ILS installations will be located is poorly understood. We recommend additional soil borings or test pits be advanced in the immediate vicinity of several ILS locations to better understand the soil and groundwater conditions. Shannon & Wilson can propose a scope and fee for conducting these explorations, if desired. Additionally, survey data in the vicinity of the generator pad and the adjacent slope is needed to better refine the slope stability analysis and design recommendations for slope stabilization. 11 CLOSURE This report was prepared for the exclusive use of the Carollo Engineers design team and the City of Renton, and in no way guarantees that any agency or its staff will reach the same conclusions as Shannon & Wilson. The analyses and conclusions contained in this report are Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 20 based on the site conditions as they are described in this report. It is assumed that the available data, site observations, and exploratory test holes are representative of the subsurface conditions throughout the site, i.e., the conditions everywhere are not significantly different from those disclosed by the explorations. The conclusions and recommendations presented in this report are based on publicly available subsurface data and subsurface explorations performed as part of this study. If there is a substantial lapse of time between submission of this report and the start of work at the site, we recommend that this report be reviewed to determine the applicability of the conclusions and recommendations, considering the changed conditions and/or elapsed time. Future events, whether natural or artificial, may alter the accuracy and applicability of these assessments. Within the limitations of scope, schedule, and budget, the conclusions presented in this report were prepared in accordance with generally accepted professional geologic/geotechnical engineering principles and practices in this area at the time this report was prepared. We make no other warranty, either expressed or implied. Unanticipated conditions are commonly encountered during construction and cannot fully be determined by merely taking soil samples or advancing test pits. Such unexpected conditions frequently require that additional expenditures be made to attain a properly constructed project. Please note that the scope of our services did not include environmental assessments or evaluations for the presence or absence of wetlands or hazardous or toxic substances in the soil, surface water, groundwater, or air on, below, or around this site. We are able to provide these services and would be pleased to discuss these with you as the need arises. Shannon & Wilson has prepared the enclosed "Important Information About Your Geotechnical/Environmental Report" to assist you and others in understanding the use and limitations of the reports. 12 REFERENCES American Society of Civil Engineers (ASCE), 2017, Minimum design loads and associated criteria for buildings and other structures: Reston, Va., American Society of Civil Engineers, ASCE Standard ASCE/SEI 7-16, 2 v. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 21 ASTM International, 2021, Standard test methods for laboratory compaction characteristics of soil using modified effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)), D1557-12(2021): West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 13 p., available: www.astm.org. Booth, D.B.; Troost, K.G.; Clague, J.J.; and Waitt, R.B.; 2003, The Cordilleran Ice Sheet: Chapter 2, in Gillespie, A., Porter, S.C., and Attwater, B., eds., The Quaternary Period in the United States: Amsterdam, the Netherlands, Elsevier Press, p. 17-43. Chrzastowski, M.J., 1983, Historical changes in Lake Washington, King County, Washington: U.S. Geological Survey Water Resources Investigations WRI 81-1182, scale 1:24,000. International Code Council, Inc., 2020, International building code 2021: Country Club Hills, Ill., International Code Council, Inc., 1 v. King County, Washington, 2024, King County iMAP: interactive mapping tool: Seattle, Wash., King County GIS Center, available: http://www.kingcounty.gov/operations/gis/Maps/iMAP.aspx. Porter, S.C.; and Swanson, T.W.; 1998, Radiocarbon age constraints on rates of advance and retreat of the Puget Lobe of the Cordilleran Ice Sheet during the last glaciation: Quaternary Research, v. 50, p. 205-213. Seattle Department of Planning and Development, 2009, Small diameter pipe piles (pin piles): Seattle, Wash., 3 p., May, available: http://www.seattle.gov/dpd/codes/dr/DR2009-10.pdf. U.S. Geological Survey (USGS), n.d., Subduction zone science – science – Cascadia: Available: https://www.usgs.gov/special-topics/subduction-zone- science/science/cascadia. Washington Emergency Management Division, 2023, Earthquake: Available: https://mil.wa.gov/earthquake. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2017 DigitalGlobe ©CNES (2017) Distribution Airbus DS © 2017 Microsoft Corporation Kennydale PROJECT LOCATION Lak e W a s h i n n t o n Mercer Island Renton Newcastle NOTE Fil e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 V i c i n i t y M a p . d w g D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S SeattleWashington ProjectLocation 90 5 97 405 0 2,000 4,000 Approximate Scale in Feet Bing Map Image adapted from aerial imageryprovided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. 104024-200 FIG. 1 VICINITY MAP December 2024 Kennydale Lakeline Sewer ImprovementsRenton, Washington Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO L A K E W A S H I N G T O N Kennydale Mountain V i e w A v e n u e N Lake Washington Boulevard N Burnett Av e n u e N N 3 0 t h S t r e e t N 3 8 t h S t r e e t SHE E T 1 SHE E T 2 SHEET 3 SHEET 4 SHEET 5 SHEET 6 SHEET 7 SHEET 8 B-5 B-4 B-2 B-3 B-1 Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : F i g u r e 2 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE KEY PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 20 40 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Park Aven u e N Boring Designation and Approximate Location LEGEND B-1 FIG. 2 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line Existing Lake Line Sewer Lateral Sewer Lateral 2727MOUNTAIN VIEW AVE 2731 MOUNTAIN VIEW AVE 2801MOUNTAIN VIEW AVE 2805MOUNTAIN VIEW AVE 2807 MOUNTAIN VIEW AVE 2811 MOUNTAIN VIEW AVE 2815 MOUNTAIN VIEW AVE 2827 MOUNTAIN VIEW AVE Mountain View Avenu e N Lake Washington Boulevard N L A K E W A S H I N G T O N Mountain View Avenue N Railroad Tracks B-5 Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 1 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 2 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 1 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line Sewer Lateral Sewer Lateral 2827MOUNTAINVIEW AVE 2907 MOUNTAIN VIEW AVE 2907 & 2909 MOUNTAIN VIEW AVE 3001MOUNTAIN VIEW AVE Existing Lake Line Sewer Lateral Sewer Lateral 3007MOUNTAIN VIEW AVE 3009 MOUNTAIN VIEW AVE 3013MOUNTAIN VIEW AVE Mountai n V i e w A v e n u e N Railroad Tracks Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 2 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 3 Ma t c h l i n e - S h e e t 1 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 2 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 20 2 4 M i c r o s o f t C o r p o r a t i o n © 2 0 2 4 M a x a r © C N E S ( 2 0 2 4 ) D i s t r i b u t i o n A i r b u s D S © 2 0 2 4 T M A P M O B I L I T Y E a r t h s t a r G e o g r a p h i c s S I O © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Sewer Lateral Existing Lake Line Sewer Lateral 3101MOUNTAIN VIEW AVE 3103 MOUNTAIN VIEW AVE Sewer Lateral Existing Lake Line 3107MOUNTAIN VIEW AVE Sewer Lateral Sewer Lateral 3111MOUNTAIN VIEW AVE 3115 MOUNTAIN VIEW AVE 3119MOUNTAIN VIEW AVE 3205 MOUNTAIN VIEW AVE 3013 MOUNTAIN VIEW AVE Mountain V i e w A v e n u e N Railroad T r a c k s L A K E W A S H I N G T O N Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 3 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 4 Ma t c h l i n e - S h e e t 2 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 3 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line 3209 MOUNTAIN VIEW AVE 3213 MOUNTAINVIEW AVE 3217 MOUNTAIN VIEW AVE Existing Lake Line Sewer Lateral 3233MOUNTAIN VIEW AVE 3307 MOUNTAIN VIEW AVE Lake Washington Boulevard N L A K E W A S H I N G T O N Mountain Vie w A v e n u e N Railroad Tracks Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 4 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 5 Ma t c h l i n e - S h e e t 3 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 4 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line Sewer Lateral 3307MOUNTAIN VIEW AVE 3401LAKE WASHINGTON BLVD Existing Lake Line Sewer Lateral 3405LAKEWASHINGTONBLVD Sewer Lateral Sewer Lateral 3401LAKEWASHINGTONBLVD 3411LAKE WASHINGTON BLVD 3501LAKE WASHINGTON BLVD L A K E W A S H I N G T O N Lake Washington B o u l e v a r d N Railroad Tracks B-4 Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 5 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 6 Ma t c h l i n e - S h e e t 4 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 5 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line Existing Lake Line Sewer Lateral Sewer Lateral SewerLateral Sewer Lateral 3605 LAKE WASHINGTON BLVD 3601LAKE WASHINGTON BLVD 3607LAKE WASHINGTON BLVD 3611 LAKE WASHINGTON BLVD 3613LAKE WASHINGTON BLVD 3619 LAKE WASHINGTON BLVD 3625LAKE WASHINGTON BLVD Sewer Lateral 3703LAKEWASHINGTONBLVD L A K E W A S H I N G T O N Railroad Tracks Lake Washington Boule v a r d N 3501 LAKE WASHINGTON BLVD B-2 B-3 Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 6 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 7 Ma t c h l i n e - S h e e t 5 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 6 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line Sewer Lateral Sewer Lateral Sewer Lateral 3707 LAKE WASHINGTON BLVD 3709 LAKE WASHINGTONBLVD 3711LAKEWASHINGTONBLVD 3713LAKEWASHINGTONBLVD 3715 LAKE WASHINGTON BLVD Existing Lake Line Sewer Lateral Sewer Lateral Sewer Lateral 3717 LAKE WASHINGTON BLVD 3719LAKEWASHINGTONBLVD 3805 LAKE WASHINGTON BLVD 3811LAKEWASHINGTONBLVD 3815 LAKE WASHINGTONBLVD 3821 LAKE WASHINGTON BLVD WASHINGTON L A K E W A S H I N G T O N Railroad Tracks Lake Washington Boulevard N B-1 Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 7 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 8 Ma t c h l i n e - S h e e t 6 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 7 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TMAP MOBILITY Earthstar Geographics SIO Existing Lake Line Sewer Lateral 3821LAKEWASHINGTONBLVD 3825 LAKE WASHINGTON BLVD 3827LAKE WASHINGTON BLVD 3837 LAKE WASHINGTON BLVD 3901LAKEWASHINGTONBLVD Existing Lake Line 3905LAKE WASHINGTON BLVD L A K E W A S H I N G T O N Railroad Track s Lake Washingto n B o u l e v a r d N Fi l e n a m e : C: \ U s e r s \ j r s \ C A D G r o u p D r o p b o x \ J D r i v e \ _ S E A \ 1 0 4 0 2 4 \ 2 0 0 \ 1 0 4 0 2 4 - 2 0 0 - S i t e P l a n s . d w g L a y o u t : S h e e t 8 D a t e : 1 1 - 1 5 - 2 0 2 4 L o g i n : J R S 104024-200 SITE PLAN Kennydale Lakeline Sewer Improvements Renton, Washington December 2024 0 40 80 Scale in Feet Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft Bing Maps reprinted with permission from Microsoft Corporation. NOTE Ma t c h l i n e - S h e e t 7 Boring Designation and Approximate Location LEGEND FIG. 3Sheet 8 of 8 B-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 A-i AP P E N D I X A : B O R I N G L O G S Appendix A: Boring Logs Appendix A Boring Logs Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Poorly Graded Gravel; Poorly Graded Gravel with Sand Well-graded Gravel; Well-Graded Gravel with Sand Lean Clay; Lean Clay with Sand or Gravel; Sandy or Gravelly, Lean Clay Fil e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 1 1 / 1 3 / 2 4 Description Term LOG KEY SOIL CLASSIFICATION Organic Inorganic HIGHLY ORGANIC SOILS Symbol / Graphic Silty Sand; Silty Sand with Gravel Silt; Silt with Sand or Gravel; Sandy or Gravelly Silt Poorly Graded Sand; Poorly Graded Sand with Gravel Silty Gravel; Silty Gravel with Sand Clayey Gravel; Clayey Gravel with Sand <5 5 to 10 15 to 25 30 to 45 >50 Term Well-graded Sand; Well-graded Sand with Gravel Organic Major Divisions Gravel(< 5% fines3) Silty orClayey Gravel(> 12% fines3) Sand(< 5% fines3) Silty orClayey Sand(> 12% fines3) SILTS AND CLAYS(liquid limit > 50) Primarily organic matter, dark in color, and organic odor GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Shannon & Wilson uses a soil identification system modified from the Unified Soil Classification System (USCS) as described on this Key.Soil descriptions are based on visual-manual procedures (ASTM D2488) and available laboratory index test results (ASTM D2487). SILTS AND CLAYS(liquid limit < 50) NOTE: For gravels and sands with5 to 12% fines3, the following areadded to the Group Name:with Silt and/or Clay or Silty Clay.Dual Symbols are used: GW-GM, GP-GM, SW-SM, SP-SMGW-GC, GP-GC, SW-SC, SP-SC Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or Gravelly, Organic Silt or Clay Elastic Silt; Elastic Silt with Sand or Gravel; Sandy or Gravelly, Elastic Silt Fat Clay; Fat Clay with Sand or Gravel; Sandy or Gravelly, Fat Clay Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or Gravelly, Organic Silt or Clay COARSE-GRAINEDSOILS(> 50% of soilis retained on theNo. 200 sieve3) FINE-GRAINEDSOILS(> 50% of soil passesthe No. 200 sieve3) Typical Identifications (USCS Group Names)2,4 Sum of the count of hammer blows to penetrate the second andthird 6-inch increments in blows per foot (bpf).Refusal: 50 blows for 6 inches or less or 10 blows for 0 inch. Percent1 Crumbles or breaks with handling or slight finger pressure. Crumbles or breaks with considerable finger pressure. Will not crumble or break with finger pressure. Description GRAVELS(> 50% of coarsefraction retained onthe No. 4 sieve3) Inorganic Peat or other Highly Organic Soils (see ASTM D4427) Clayey Sand; Clayey Sand with Gravel Dry Moist Wet Term Absence of moisture, dusty, dry to the touch. Damp but no visible water. Visible free water, from below water table. Term140-pound weight with a 30-inch free fall. Hammer types vary(e.g., automatic, rope and cathead). If available, the hammer typeand energy ratio (E-ratio) is noted on the boring log. Description Term Nonplastic LowPlasticity MediumPlasticity Slickensided Lensed Laminated Interbedded Homogeneous Fissured Description Barrel I.D. / O.D. = 1.5 inches / 2 inches (liner not used)Barrel Length = 30 inches; Shoe I.D. = 1.375 inches Blocky Cannot roll a 1/8-inch thread at any water content. A thread can barely be rolled and a lump cannot be formed when drier thanthe plastic limit. A thread is easy to roll and not much time in rolling is required to reach theplastic limit. The thread cannot be rerolled after reaching the plastic limit. Alump crumbles when drier than the plastic limit. It takes considerable time rolling and kneading to reach the plastic limit. Athread can be rerolled several times after reaching the plastic limit. A lumpcan be formed without crumbling when drier than the plastic limit. Cohesive soil that can be broken down into small angular lumps thatresist further breakdown. Breaks along definite planes or fractures with little resistance. Same color and appearance throughout. Alternating layers at least 1/4 inch thick of varying material or color.Singular: bed Alternating layers less than 1/4 inch thick of varying material or color.Singular: lamination Inclusion of small pockets of different soils, such as small lenses ofsand scattered through a mass of clay. Fracture planes appear polished or glossy, sometimes striated. HighPlasticity Term Sampler N-Value(N)1 Term Hammer Very Soft Soft Medium Stiff Stiff Very Stiff Hard Very Loose Loose Medium Dense Dense Very Dense N2 (bpf) 0 - 4 4 - 10 10 - 30 30 - 50 > 50 TV3 (tsf) 0 - 0.12 0.12 - 0.25 0.25 - 0.5 0.5 - 1 1 - 2 > 2 N2 (bpf) 0 - 2 2 - 4 4 - 8 8 - 15 15 - 30 > 30 PP3 (tsf) 0 - 0.25 0.25 - 0.5 0.5 - 1 1 - 2 2 - 4 > 4 Description Trace Few Little Some Mostly Weak Moderate Strong Term SANDS(> 50% of coarsefraction passesthe No. 4 sieve3) Page 1 of 2 Exhibit A: Unified Soil Classification System (USCS)1 Exhibit G: Percentages Exhibit E: Soil Moisture Content1 EXHIBIT A NOTES:1. Adapted, with permission, from USACE Tech Memo 3-357, ASTM D2487, and ASTM D2488.2. Borderline symbols (symbols separated by a slash) indicate that the soil characteristics are close to the defining boundary between two groups (e.g., CL/ML = Lean Clay to Silt; SP-SM/SM = Sand with Silt to Silty Sand).3. No. 4 size = 4.75 millimeters (mm) = 0.187 inch; No. 200 sieve size = 0.075 mm = 0.003 inch. Particles smaller 0.075 mm are termed "fines".4. Poorly graded indicates a narrow range or missing grain sizes. Well-graded indicates a full-range and even distribution of grain sizes.5. If cobbles and/or boulders are observed, "with cobbles" or "with boulders" or "with cobbles and boulders" is added to the Group Name. EXHIBIT E NOTE:1. Adapted, with permission, from ASTM D2488 (Figure 2). EXHIBIT G NOTE:1. Percent estimated by weight for sand and gravel,and by volume for cobbles, organics, and othernon-soil material (e.g., rubble, debris). EXHIBIT D NOTE:1. Adapted, with permission, from ASTM D2488. Exhibit C: Soil Structure1 Exhibit D: Soil Plasticity1 EXHIBIT C NOTE:1. Adapted, with permission, from ASTM D2488. Exhibit B-3: Relative Densityof Cohesionless SoilsExhibit B-1: Standard Penetration Test (SPT) EXHIBIT B NOTES:1. N-values shown on boring logs are as recorded in the field and have not been corrected for hammer energy, overburden, or other factors. Where the hammer E-ratio is available, the N-value normalized to a ratio of 60% (N60) is listed.2. Based on ASTM Standard D1586. Relative densities/consistencies noted on the boring logs are based on uncorrected N-values.3. PP = pocket penetrometer; TV = torvane, tsf = tons per square foot. Correlations based on experience and multiple published references. Exhibit B-2: Relative Consistencyof Cohesive Soils EXHIBIT F NOTE:1. Adapted, with permission, from ASTM D2488. Exhibit F: Soil Cementation1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com ATDbpfdia, diam Elev.ENVETRFCFeOft or 'galGP GWTHSAID in or "inclksf lbsLLmm NN60NA, n/a NENPNRNWOCODOWpcf PIPIDPL PMTPPppm psiPTREC REFRQDSC SESPTSWTPtsfTVUCS, quUSCS VSTVWPWC WOHWOR at time of drillingblows per footdiameter elevationenvironmental sampleenergy transfer ratio (hammer)fines content (< 0.075 mm)iron oxidefoot or feetgallonsgeoprobe groundwater tablehollow-stem augerinside diameter or identification inchinclinometerkips per square foot poundsliquid limitmillimeter field (uncorrected) SPT N-valueSPT N-value corrected for 60% ETRnot applicable or not available northeastnonplasticno recoverynorthwestorganic contentoutside diameterobservation wellpounds per cubic foot plasticity indexphotoionization detectorplastic limit pressuremeter testpocket penetrometer readingparts per million pounds per square inchnonstandard penetration test N-valuerecovery refusalrock quality designation (ASTM D6032)sonic core southeastStandard Penetration Test (ASTM D1586)southwesttest pittons per square foottor vane readingunconfined compressive strengthUnified Soil Classification System vane shear testvibrating wire piezometernatural water content weight of hammerweight of rods REFERENCE: Brown, E. T., ed., 1981, Rock characterization, testing & monitoring: International Society of Rock Mechanics (ISRM) suggested methods: Oxford,Pergamon Press, 211 p. Fil e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 1 1 / 1 3 / 2 4 LOG KEY SampleNumber SampleType Water LevelMeasured at Datein Well or VWP Well/VWP ID No. Water LevelDuring Drilling MeasurementDate (M-D-YY) Blank pipe orinstrument casing Perforated orslotted pipe VWP and electriclead EnvironmentalSample Taken Split spoon (SS)(diameters vary) Modified California(MC) sampler Sonic core (SC) run(typically soil) Other REFERENCE: Loehr, J. E.; Lutenegger, A.; Rosenblad, B.; and Boeckmann, A., 2016,Geotechnical site characterization: U.S. Federal Highway Administration Report FHWANHI-16-072, Geotechnical Engineering Circular no. 5, 1 v. Rock Quality Designation(RQD) in % Core Recovery(REC) in % ROCK CLASSIFICATION Graphic Description Description Irregular patches of different colors. Soil disturbance or mixing by plants or animals. Nonsorted sediment; sand and gravel in silt and/or clay matrix. Material brought to surface by drilling action. Material that caved from sides of borehole. Disturbed texture, mix of strengths. Sharp edges and unpolished planar surfaces. Similar to angular, but with rounded edges. Nearly planar sides with well-rounded edges. Smoothly curved sides with no edges. Width to thickness ratio > 3. Width to thickness ratio < 3. Term Angular Subangular Subrounded Rounded Flat Elongated Term Mottled Bioturbated Diamict Cuttings Slough Sheared Core run (typicallyrock) Sheath (SH) (usedfor geoprobes) Graphic Description SYMBOLOGY AND GRAPHICS Graphic Description Graphic Description S-5(SPT) Description Graphic Description Graphic Description SOIL CLASSIFICATION # # Gray barindicates percent ofsample length recovered. Bentonite-cementgrout Bentonitegrout Bentonitechips Surfacecement seal Sand filterpack Slough (holecaved) Shannon & Wilson uses a rock classification system modified from the system recommended by the International Society for Rock Mechanics (ISRM).Copyright limitations prevent us from reproducing summary tables from the ISRM system on this Key. General descriptions are provided in Exhibit M. (continued) Term Strength General Description Weathering Fabric Ranges from extremely weak (qu = 36 to 135 psi) to extremely strong (qu > 36,250 psi), andis based on the ability to break the rock with a hammer or scrape the rock with a knife. Ranges from fresh (no visible signs of weathering) to completely weathered, based onobserved degree of discoloration, decomposition, and/or disintegration. When the rockmaterial has completely converted to soil, it is termed a residual soil. Describes the rock structure based on observed layering, tendency to break, anddistribution of minerals (e.g., massive, bedded, foliated). For discontinuities: Includes rough, smooth, and slickensided, and includes otherdescriptive terms (e.g., stepped, undular, irregular, planar). For discontinuities: Ranges from extremely close (< 1 inch) to extremely wide (> 20 feet). For discontinuities: Ranges from very low to very high. Description of discontinuities (joints, fractures, bedding planes, etc.), observations ofpotential displacement, gouge, shear, etc. Persistence Roughness Spacing Term Equation SPT split spoon(2-inch OD) Grab (GB) fromcuttings or excavation Tube (TB) (e.g.,Shelby, piston) ACRONYMS AND ABBREVIATIONS Length of Core in Pieces > 4 in Length of Core Run100% x 100% x Exhibit H: Particle Angularity and Shape1 EXHIBIT H NOTE:1. Adapted, with permission, from ASTM D2488. Length of Core Recovered Length of Core Run No rock names defined for this Project Page 2 of 2 Exhibit I: Additional Descriptive Terms SOIL CLASSIFICATION REFERENCES: ASTM International, [current edition], Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, available:www.astm.org. U.S. Army Corps of Engineers, 1953, The unified soil classification system: Vicksburg, Miss., Waterways ExperimentStation, Technical Memorandum 3-357, 2 v., March. See Page 1 for Soil Classification Exhibits A through G Exhibit M: General Rock Descriptive Terms - ISRM Exhibit L: Other Log Symbols Exhibit J: Sample and Run Graphics Exhibit K: Hole Backfill and Instrument Graphics Exhibit N: Rock Name Graphics Exhibit O: Recovery and RQD Equations1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 15.4 As-Built S-1(SPT) S-2(SPT) S-3(SPT) S-4(SPT) S-5(SPT) S-6(SPT)15.4 N = 7,23,50/5"(73/11" bpf) N = 24,50/5"(50/5" bpf) N = 34,40/5"(40/5" bpf) N = 50/5"(50/5" bpf) N = 22,50/6"(50/6" bpf) N = 50/5"(50/5" bpf) DRILLING INFORMATION Drilling Method: Drilling Company: Drill Rig Equipment: Hole Size: Hollow Stem Auger Geologic Drill Partners Bobcat MT55 7 inch EXPLORATION INFORMATION Total Depth: Top Elevation: Vertical Datum: Latitude: Longitude: Horizontal Datum: 15.4 feet ~28 feet NAVD88 WGS [GCS1984] ~ 47.5253 degrees ~ -122.2064 degrees FLUSHMOUNT FINAL Logged by: Review by: Version: DYC TMK 1 = WC% = FC% Uncorrected N-value, bpf Uncorrected, Penetration N-value, bpfNOTES: - Refer to LOG KEY for explanation of symbols, codes, abbreviations, and definitions. - Groundwater level, if indicated above, is for the date specified and may vary. - Group symbol is based on visual-manual identification and selected lab testing. - Report text contains limitations and information needed to contextually understand this log. Sample NumberSample Type Symbols (See separate LOG KEY for additional symbols, acronyms, and definitions) Abbreviations BASIC LEGEND S-5(SPT) Standard Penetration Test (SPT) blows per 6-inch increment Penetration test (not SPT) blows per 6-inch increment Blows per foot for penetration test Natural water content (%)Fines content (% grains smaller than 0.075 mm)Plasticity index (Atterberg Limits) N PT bpf WCFCPI # # Water LevelMeasured at Datein Well or VWP ID No.MeasurementDate (M-D-YY) Gray bar indicates percentof sample length recovered. Well Tag No.:BNZ072 n/a 140 lbs/30 inches n/a Rod Type/Dia.: Hammer Wt. / Drop: Hammer ETR:Hole Start Date: Hole Finish Date: August 28, 2024 August 28, 2024 BORING LOG De p t h ( f e e t ) 5 10 15 De p t h ( f e e t ) Ap p r o x . El e v . ( f e e t ) LabDataGr a p h i c Multiple Items Plotted(see bottom legend on Page 1) 500 100 FieldData Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | R p t : B O R I N G L O G | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Kennydale Lakeline Sewer Improvements Renton, Washington WC=10%pH=7.7RES=4200OhmCm WC=9%FC=39%SC=57%GC=5% WC=9% WC=10% WC=11%pH=8.4RES=2200OhmCm WC=8% >> >> >> >> >> >> 5 10 15 B-1 25 20 15 Page 1 of 1 Very dense, brown to olive-brown, SILTY SAND (SM);moist; trace fine, subrounded to subangular gravel;medium to fine sand, trace coarse sand. (Ovt) BOTTOM OF HOLE AT 15.4 FEET Material Description and Other Observations Sa m p l e s #1 9- 4 - 2 4 # 1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 0.3 3.2 4.5 16.5 As-Built S-1(SPT) S-2(SPT) S-3(SPT) S-4(SPT) S-5(SPT) S-6(SPT) 16.5 N = 5,4,6(10 bpf) N = 9,16,24(40 bpf) N = 29,50/5"(50/5" bpf) N = 30,50/4"(50/4" bpf) N = 50/6"(50/6" bpf) N = 11,23,30(53 bpf) DRILLING INFORMATION Drilling Method: Drilling Company: Drill Rig Equipment: Hole Size: Hollow Stem Auger Geologic Drill Partners Bobcat MT55 7 inch EXPLORATION INFORMATION Total Depth: Top Elevation: Vertical Datum: Latitude: Longitude: Horizontal Datum: 16.5 feet ~23 feet NAVD88 WGS [GCS1984] ~ 47.5237 degrees ~ -122.2074 degrees FLUSHMOUNT FINAL Logged by: Review by: Version: DYC TMK 1 = WC% = FC% Uncorrected N-value, bpf Uncorrected, Penetration N-value, bpf Liquid LimitPlastic Limit NOTES: - Refer to LOG KEY for explanation of symbols, codes, abbreviations, and definitions. - Groundwater level, if indicated above, is for the date specified and may vary. - Group symbol is based on visual-manual identification and selected lab testing. - Report text contains limitations and information needed to contextually understand this log. Sample NumberSample Type Symbols (See separate LOG KEY for additional symbols, acronyms, and definitions) Abbreviations BASIC LEGEND S-5(SPT) Standard Penetration Test (SPT) blows per 6-inch increment Penetration test (not SPT) blows per 6-inch increment Blows per foot for penetration test Natural water content (%)Fines content (% grains smaller than 0.075 mm)Plasticity index (Atterberg Limits) N PT bpf WCFCPI Water LevelDuringDrilling # # Water LevelMeasured at Datein Well or VWP ID No.MeasurementDate (M-D-YY) Gray bar indicates percentof sample length recovered. Well Tag No.:BNZ073 n/a 140 lbs/30 inches n/a Rod Type/Dia.: Hammer Wt. / Drop: Hammer ETR:Hole Start Date: Hole Finish Date: August 28, 2024 August 28, 2024 BORING LOG De p t h ( f e e t ) 5 10 15 De p t h ( f e e t ) Ap p r o x . El e v . ( f e e t ) LabDataGr a p h i c Multiple Items Plotted(see bottom legend on Page 1) 500 100 FieldData Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | R p t : B O R I N G L O G | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Kennydale Lakeline Sewer Improvements Renton, Washington WC=16%FC=16%SC=64%GC=20%WC=16%FC=45%SC=39%GC=16%LL/PI=27/11 WC=13%pH=7.5RES=8900OhmCm WC=8% WC=8% WC=8% WC=11%pH=8.6RES=4000OhmCm >> >> >> AT D 5 10 15 B-2 20 15 10 Page 1 of 1 ASPHALT Loose, brown, POORLY GRADED SAND WITH SILT (SP-SM); wet; trace fine, subrounded to subangulargravel; medium to fine sand. (Hf) Stiff, brown, CLAYEY SAND WITH GRAVEL (SC); moist; trace fine subrounded gravel; medium to fine sand;low to medium plasticity; mottled iron oxide staining.(Hf) Dense to very dense, brown to olive-gray, SILTY SAND (SM); wet to moist; trace to few fine, subrounded tosubangular gravel; medium to fine sand, trace coarsesand. (Qvt) BOTTOM OF HOLE AT 16.5 FEET Material Description and Other Observations Sa m p l e s #1 9- 3 - 2 4 # 1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 0.3 4.5 7.9 12.0 13.3 14.5 17.0 19.5 25.0 25.9 As-Built S-1(SPT) S-2(SPT) S-3(SPT) S-4(SPT) S-5(SPT) S-6(SPT) S-7(SPT) S-8(SPT) S-9(SPT)25.9 N = 3,4,4(8 bpf) N = 3,3,2(5 bpf) N = 8,4,4(8 bpf) N = 3,3,6(9 bpf) N = 3,6,5(11 bpf) N = 3,4,4(8 bpf) N = 5,5,5(10 bpf) N = 4,11,15(26 bpf) NR N = 14,50/5"(50/5" bpf) DRILLING INFORMATION Drilling Method: Drilling Company: Drill Rig Equipment: Hole Size: Hollow Stem Auger Geologic Drill Partners Acker Recon 7 inch EXPLORATION INFORMATION Total Depth: Top Elevation: Vertical Datum: Latitude: Longitude: Horizontal Datum: 25.9 feet ~62 feet NAVD88 WGS [GCS1984] ~ 47.5229 degrees ~ -122.2071 degrees FLUSHMOUNT FINAL Logged by: Review by: Version: DYC TMK 1 = WC% = FC% Uncorrected N-value, bpf Uncorrected, Penetration N-value, bpf Liquid LimitPlastic Limit NOTES: - Refer to LOG KEY for explanation of symbols, codes, abbreviations, and definitions. - Groundwater level, if indicated above, is for the date specified and may vary. - Group symbol is based on visual-manual identification and selected lab testing. - Report text contains limitations and information needed to contextually understand this log. Sample NumberSample Type Symbols (See separate LOG KEY for additional symbols, acronyms, and definitions) Abbreviations BASIC LEGEND S-5(SPT) Standard Penetration Test (SPT) blows per 6-inch increment Penetration test (not SPT) blows per 6-inch increment Blows per foot for penetration test Natural water content (%)Fines content (% grains smaller than 0.075 mm)Plasticity index (Atterberg Limits) N PT bpf WCFCPI Water LevelDuringDrilling # # Water LevelMeasured at Datein Well or VWP ID No.MeasurementDate (M-D-YY) Gray bar indicates percentof sample length recovered. Well Tag No.:BNZ076 n/a 140 lbs/30 inches n/a Rod Type/Dia.: Hammer Wt. / Drop: Hammer ETR:Hole Start Date: Hole Finish Date: August 30, 2024 August 30, 2024 BORING LOG De p t h ( f e e t ) 5 10 15 20 25 De p t h ( f e e t ) Ap p r o x . El e v . ( f e e t ) LabDataGr a p h i c Multiple Items Plotted(see bottom legend on Page 1) 500 100 FieldData Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | R p t : B O R I N G L O G | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Kennydale Lakeline Sewer Improvements Renton, Washington WC=20%LL/PI=34/13 WC=18% WC=17%WC=23% WC=26%LL/PI=30/11 WC=20% WC=27% WC=21%LL/PI=29/11 WC=21%pH=8RES=4100OhmCm WC=9%FC=37%SC=55%GC=9% >> AT D 5 10 15 20 25 B-3 60 55 50 45 40 Page 1 of 1 ASPHALT Medium stiff, gray to brown, LEAN CLAY (CL); moist; trace to few fine sand; medium plasticity; mottled ironoxide staining. (Qvrl) Loose, red-brown, SILTY SAND (SM); moist; fine to medium sand; nonplastic.(Qvro) Medium stiff to stiff, yellow-brown to light brown, LEANCLAY (CL); moist; trace to few fine to medium sand; medium to low plasticity; mottled iron oxide staining. (Qvrl) Medium dense, yellow-brown, POORLY GRADEDSAND WITH SILT (SP-SM); moist; trace finesubrounded gravel; fine to medium sand. (Qvro) Stiff, light brown, SILTY CLAY WITH SAND (CL-ML); moist to wet; trace fine, subrounded to subangular gravel;fine sand; mottled iron oxide staining. (Qvrl) Medium stiff, yellow-brown, LEAN CLAY WITH SAND (CL); moist; trace fine, subrounded to subangular gravel;medium to fine sand; medium to low plasticity.(Qvrl) Medium stiff, gray, LEAN CLAY (CL); moist to wet; trace fine to medium sand; low to medium plasticity.(Qvrl) NO RECOVERY Dense to very dense, gray, SILTY SAND (SM); moist;trace to few fine, subrounded to subangular gravel; medium to fine sand.(Qvt) BOTTOM OF HOLE AT 25.9 FEET Material Description and Other Observations Sa m p l e s #1 9-3 - 2 4 # 1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 0.7 7.0 14.0 15.9 As-Built S-1(SPT) S-2(SPT) S-3(SPT) S-4(SPT) S-5(SPT) S-6(SPT) 15.9 N = 4,6,10(16 bpf) N = 10,14,23(37 bpf) N = 12,22,42(64 bpf) N = 21,31,40(71 bpf) N = 19,31,50/5"(81/11" bpf) N = 10,50/5"(50/5" bpf) DRILLING INFORMATION Drilling Method: Drilling Company: Drill Rig Equipment: Hole Size: Hollow Stem Auger Geologic Drill Partners Acker Recon 7 inch EXPLORATION INFORMATION Total Depth: Top Elevation: Vertical Datum: Latitude: Longitude: Horizontal Datum: 15.9 feet ~41 feet NAVD88 WGS [GCS1984] ~ 47.5221 degrees ~ -122.2079 degrees FLUSHMOUNT FINAL Logged by: Review by: Version: DYC TMK 1 = WC% = FC% Uncorrected N-value, bpf Uncorrected, Penetration N-value, bpfNOTES: - Refer to LOG KEY for explanation of symbols, codes, abbreviations, and definitions. - Groundwater level, if indicated above, is for the date specified and may vary. - Group symbol is based on visual-manual identification and selected lab testing. - Report text contains limitations and information needed to contextually understand this log. Sample NumberSample Type Symbols (See separate LOG KEY for additional symbols, acronyms, and definitions) Abbreviations BASIC LEGEND S-5(SPT) Standard Penetration Test (SPT) blows per 6-inch increment Penetration test (not SPT) blows per 6-inch increment Blows per foot for penetration test Natural water content (%)Fines content (% grains smaller than 0.075 mm)Plasticity index (Atterberg Limits) N PT bpf WCFCPI Water LevelDuringDrilling # # Water LevelMeasured at Datein Well or VWP ID No.MeasurementDate (M-D-YY) Gray bar indicates percentof sample length recovered. Well Tag No.:BNZ075 n/a 140 lbs/30 inches n/a Rod Type/Dia.: Hammer Wt. / Drop: Hammer ETR:Hole Start Date: Hole Finish Date: August 29, 2024 August 29, 2024 BORING LOG De p t h ( f e e t ) 5 10 15 De p t h ( f e e t ) Ap p r o x . El e v . ( f e e t ) LabDataGr a p h i c Multiple Items Plotted(see bottom legend on Page 1) 500 100 FieldData Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | R p t : B O R I N G L O G | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Kennydale Lakeline Sewer Improvements Renton, Washington WC=12%pH=7.2RES=4800OhmCm WC=12% WC=10%pH=7.4RES=5000OhmCm WC=8%FC=32%SC=55%GC=13% WC=9% WC=10%FC=6%SC=70%GC=24% >> >> AT D 5 10 15 B-4 40 35 30 Page 1 of 1 ASPHALT Medium dense to dense, red-brown to yellow-brown,SILTY SAND (SM); moist; trace fine, subrounded to subangular gravel; fine sand.(Qvro) -5.0 to 7.5 feet: faintly laminated Very dense, brown to yellow-brown, SILTY SAND (SM);moist; trace to few fine to coarse, subrounded to subangular gravel; medium to fine sand.(Qvt) Very dense, dark brown, POORLY GRADED SANDWITH SILT AND GRAVEL (SP-SM); moist to wet; fine, subrounded to subangular gravel; fine to coarse sand.(Qva) BOTTOM OF HOLE AT 15.9 FEET Material Description and Other Observations Sa m p l e s #1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 9.5 15.5 As-Built S-1(SPT) S-2(SPT) S-3(SPT) S-4(SPT) S-5(SPT) S-6(SPT)15.5 N = 8,22,39(61 bpf) N = 20,35,50/5"(85/11" bpf) N = 11,35,46(81 bpf) N = 35,50/6"(50/6" bpf) N = 50/5"(50/5" bpf) N = 50/6"(50/6" bpf) DRILLING INFORMATION Drilling Method: Drilling Company: Drill Rig Equipment: Hole Size: Hollow Stem Auger Geologic Drill Partners Acker Recon 7 inch EXPLORATION INFORMATION Total Depth: Top Elevation: Vertical Datum: Latitude: Longitude: Horizontal Datum: 15.5 feet ~37 feet NAVD88 WGS [GCS1984] ~ 47.5175 degrees ~ -122.2095 degrees FLUSHMOUNT FINAL Logged by: Review by: Version: DYC TMK 1 = WC% = FC% Uncorrected N-value, bpf Uncorrected, Penetration N-value, bpfNOTES: - Refer to LOG KEY for explanation of symbols, codes, abbreviations, and definitions. - Groundwater level, if indicated above, is for the date specified and may vary. - Group symbol is based on visual-manual identification and selected lab testing. - Report text contains limitations and information needed to contextually understand this log. Sample NumberSample Type Symbols (See separate LOG KEY for additional symbols, acronyms, and definitions) Abbreviations BASIC LEGEND S-5(SPT) Standard Penetration Test (SPT) blows per 6-inch increment Penetration test (not SPT) blows per 6-inch increment Blows per foot for penetration test Natural water content (%)Fines content (% grains smaller than 0.075 mm)Plasticity index (Atterberg Limits) N PT bpf WCFCPI Water LevelDuringDrilling # # Water LevelMeasured at Datein Well or VWP ID No.MeasurementDate (M-D-YY) Gray bar indicates percentof sample length recovered. Well Tag No.:BNZ074 n/a 140 lbs/30 inches n/a Rod Type/Dia.: Hammer Wt. / Drop: Hammer ETR:Hole Start Date: Hole Finish Date: August 29, 2024 August 29, 2024 BORING LOG De p t h ( f e e t ) 5 10 15 De p t h ( f e e t ) Ap p r o x . El e v . ( f e e t ) LabDataGr a p h i c Multiple Items Plotted(see bottom legend on Page 1) 500 100 FieldData Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | R p t : B O R I N G L O G | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Kennydale Lakeline Sewer Improvements Renton, Washington WC=11%pH=7.3RES=6300OhmCm WC=9%pH=7.2RES=8000OhmCm WC=9%FC=43%SC=45%GC=12% WC=11% WC=10%FC=57%SC=38%GC=5% WC=10%FC=62%SC=34%GC=5% >> >> >> >> AT D 5 10 15 B-5 35 30 25 Page 1 of 1 Very dense, olive to yellow-brown, SILTY SAND (SM);moist to wet; trace to few fine to coarse, subrounded tosubangular gravel; fine to medium sand. (Qvt) -5.0 to 7.5 feet: mottle iron oxide staining Very dense, brown to gray, SANDY SILT (ML); moist; trace fine, subrounded to subangular gravel; fine to medium sand.(Qvt) BOTTOM OF HOLE AT 15.5 FEET Material Description and Other Observations Sa m p l e s #1 9-6 - 2 4 # 1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 B-i AP P E N D I X B : LA B O R A T O R Y T E S T R E S U L T S Appendix B: Laboratory Test Results Appendix B Laboratory Test Results CONTENTS Table B-1 Summary of Laboratory Test Results Grain Size Distribution Test Results Atterberg Limits Test Results Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements Renton, Washington TopDepth SampleNumber SampleType SPT Blow Count USCS GroupSymbol WaterContent GravelPercent SandPercent FinesPercent Coefficient of Uniformity, Cu Coefficient of Curvature, Cc Liquid Limit,LL Plastic Limit,PL Non- Plastic,NP pH Minimum Resistivity per AASHTO T288 USCS Group Name (feet)(bpf)(%)(%)(%)(%)(%)(%)(ohm-cm) 2.5 S-1 SPT 73/11"9.7 7.70 4,200 5 S-2 SPT 50/5"SM 9.0 5 57 39 SILTY SAND** 7.5 S-3 SPT 40/5"8.6 10 S-4 SPT 0/5"10.0 12.5 S-5 SPT 50/6"11.0 8.40 2,200 15 S-6 SPT 0/5"8.0 2.5 S-1 SPT 10 15.7 20*64*16*Sieve analysis only - no Atterberg Limits: Group Name not estimated 3.2 S-1 SPT 10 SC 16.0 16*39*45*27 16 CLAYEY SAND with GRAVEL B 5 S-2 SPT 40 12.7 7.50 8,900 7.5 S-3 SPT 50/5"8.2 10 S-4 SPT 50/4"8.3 12.5 S-5 SPT 0/6"8.3 15 S-6 SPT 53 10.6 8.60 4,000 2.5 S-1 SPT 8 20.2 34 21 Atterberg Limits only - no sieve analysis: Group Name not estimated 5 S-2 SPT 5 18.1 7.5 S-3 SPT 8 16.9 7.9 S-3 SPT 8 23.3 10 S-4 SPT 9 25.8 30 19 Atterberg Limits only - no sieve analysis: Group Name not estimated 12.5 S-5 SPT 11 20.0 13.25 S-5 SPT 11 27.0 15 S-6 SPT 8 21.1 29 18 Atterberg Limits only - no sieve analysis: Group Name not estimated 17.5 S-7 SPT 10 20.9 8.00 4,100 25 S-9 SPT 50/5"9.0 9*55*37*Sieve analysis only - no Atterberg Limits: Group Name not estimated 2.5 S-1 SPT 16 12.4 7.20 4,800 5 S-2 SPT 37 12.1 7.5 S-3 SPT 64 9.5 7.40 5,000 10 S-4 SPT 71 8.3 13*55*32*Sieve analysis only - no Atterberg Limits: Group Name not estimated 12.5 S-5 SPT 81/11"9.1 15 S-6 SPT 50/5"10.0 24 70 6 5.7 0.8 Sieve analysis only - no Atterberg Limits: Group Name not estimated 2.5 S-1 SPT 61 10.7 7.30 6,300 5 S-2 SPT 85/11"9.3 7.20 8,000 7.5 S-3 SPT 81 9.0 12*45*43*Sieve analysis only - no Atterberg Limits: Group Name not estimated B-4 B-4 B-5 B-5 B-5 B-4 B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-4 B-4 B-4 B-3 B-1 B-1 B-1 B-2 B-2 B-2 B-2 B-2 B-2 B-2 B-3 B-1 Table B-1: Summary of Laboratory Testing Exploration Designation B-1 B-1 104024-200 104024-R1-Summary Table_2024.10.18.xlsx-Summary Table Sheet 1 of 2 11/17/2024 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements Renton, Washington TopDepth SampleNumber SampleType SPT Blow Count USCS GroupSymbol WaterContent GravelPercent SandPercent FinesPercent Coefficient of Uniformity, Cu Coefficient of Curvature, Cc Liquid Limit,LL Plastic Limit,PL Non- Plastic,NP pH Minimum Resistivity per AASHTO T288 USCS Group Name (feet)(bpf)(%)(%)(%)(%)(%)(%)(ohm-cm) Table B-1: Summary of Laboratory Testing Exploration Designation 10 S-4 SPT 50/6"10.5 12.5 S-5 SPT 0/5"9.7 5*38*57*Sieve analysis only - no Atterberg Limits: Group Name not estimated 15 S-6 SPT 0/6"9.6 5*34*62*Sieve analysis only - no Atterberg Limits: Group Name not estimated NOTES: * ** B-5 B-5 Sample specimen weight did not meet required minimum mass for the test.; bpf = blows per foot; ohm-cm = ohm-centimeter; SPT = 2-inch Outside Diameter Split-Spoon Sample; USCS = Unified Soil Classification System Where indicated by **, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the grain size distribution/Atterberg Limits test results. B-5 104024-200 104024-R1-Summary Table_2024.10.18.xlsx-Summary Table Sheet 2 of 2 11/17/2024 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the grain size distribution test results.ABBREVIATIONS: NAT WC = natural moisture content; RVW = reviewed by; STD = Standard; USCS = Unified Soil Classification System code; ~ = approximately (used when measured but not greater than 0.5%) 0 10 20 30 40 50 60 70 80 90 100 0.00124680.0124680.12468124681024681002 3"#200#4 #103/4"0.001 DEPTH(feet) MEDIUM TESTBY/RVW RXADJB TESTSTD D6913B-1, S-2 SILTY SAND * FINE SAND FINES: SILT OR CLAY GRAIN SIZE IN MILLIMETERS 5.0 EXPLORATION ANDSAMPLE NUMBER SM USCSSYMBOLUNIFIED SOIL CLASSIFICATION SYSTEM (USCS)GROUP NAME GRAIN SIZE DISTRIBUTION TEST RESULTS PE R C E N T F I N E R B Y W E I G H T PE R C E N T C O A R S E R B Y W E I G H T SIZE OF MESH OPENING IN INCHES NO. OF MESH OPENINGS PER INCH, U.S. STANDARD 0.01 COBBLES COARSE GRAVEL GRAIN SIZE IN MILLIMETERS FINE COARSE 100 90 80 70 60 50 40 30 20 10 0 GRAVEL%SAND%FINES%TEST NOTE 12"#40 57 395 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 NATWC % 9.0 B-1 Page 1 of 1 SIEVE ANALYSIS HYDROMETER ANALYSIS Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the grain size distribution test results.ABBREVIATIONS: NAT WC = natural moisture content; RVW = reviewed by; STD = Standard; USCS = Unified Soil Classification System code; ~ = approximately (used when measured but not greater than 0.5%) 0 10 20 30 40 50 60 70 80 90 100 0.00124680.0124680.12468124681024681002 3"#200#4 #103/4"0.001 DEPTH(feet) MEDIUM TESTBY/RVW RXADJB TDTDJB TESTSTD D6913 D6913 B-2, S-1 B-2, S-1 Sieve analysis only - no Atterberg Limits:Group Name not estimated A CLAYEY SAND with GRAVEL B FINE SAND FINES: SILT OR CLAY GRAIN SIZE IN MILLIMETERS 2.5 3.2 EXPLORATION ANDSAMPLE NUMBER SC USCSSYMBOLUNIFIED SOIL CLASSIFICATION SYSTEM (USCS)GROUP NAME GRAIN SIZE DISTRIBUTION TEST RESULTS PE R C E N T F I N E R B Y W E I G H T PE R C E N T C O A R S E R B Y W E I G H T SIZE OF MESH OPENING IN INCHES NO. OF MESH OPENINGS PER INCH, U.S. STANDARD 0.01 COBBLES COARSE GRAVEL GRAIN SIZE IN MILLIMETERS FINE COARSE 100 90 80 70 60 50 40 30 20 10 0 The sample did not meet test standard's minimumrequirements The sample did not meet test standard's minimumrequirements GRAVEL%SAND%FINES%TEST NOTE 12"#40 64 39 16 45 20 16 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 NATWC % 15.7 16.0 B-2 Page 1 of 1 SIEVE ANALYSIS HYDROMETER ANALYSIS Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the grain size distribution test results.ABBREVIATIONS: NAT WC = natural moisture content; RVW = reviewed by; STD = Standard; USCS = Unified Soil Classification System code; ~ = approximately (used when measured but not greater than 0.5%) 0 10 20 30 40 50 60 70 80 90 100 0.00124680.0124680.12468124681024681002 3"#200#4 #103/4"0.001 DEPTH(feet) MEDIUM TESTBY/RVW RXADJB TESTSTD D6913B-3, S-9 Sieve analysis only - no Atterberg Limits:Group Name not estimated FINE SAND FINES: SILT OR CLAY GRAIN SIZE IN MILLIMETERS 25.0 EXPLORATION ANDSAMPLE NUMBER USCSSYMBOLUNIFIED SOIL CLASSIFICATION SYSTEM (USCS)GROUP NAME GRAIN SIZE DISTRIBUTION TEST RESULTS PE R C E N T F I N E R B Y W E I G H T PE R C E N T C O A R S E R B Y W E I G H T SIZE OF MESH OPENING IN INCHES NO. OF MESH OPENINGS PER INCH, U.S. STANDARD 0.01 COBBLES COARSE GRAVEL GRAIN SIZE IN MILLIMETERS FINE COARSE 100 90 80 70 60 50 40 30 20 10 0 The sample did not meet test standard's minimumrequirements GRAVEL%SAND%FINES%TEST NOTE 12"#40 55 379 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 NATWC % 9.0 B-3 Page 1 of 1 SIEVE ANALYSIS HYDROMETER ANALYSIS Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the grain size distribution test results.ABBREVIATIONS: NAT WC = natural moisture content; RVW = reviewed by; STD = Standard; USCS = Unified Soil Classification System code; ~ = approximately (used when measured but not greater than 0.5%) 0 10 20 30 40 50 60 70 80 90 100 0.00124680.0124680.12468124681024681002 3"#200#4 #103/4"0.001 DEPTH(feet) MEDIUM TESTBY/RVW SJDDJB RXADJB TESTSTD D6913 D6913 B-4, S-4 B-4, S-6 Sieve analysis only - no Atterberg Limits:Group Name not estimated Sieve analysis only - no Atterberg Limits:Group Name not estimated FINE SAND FINES: SILT OR CLAY GRAIN SIZE IN MILLIMETERS 10.0 15.0 EXPLORATION ANDSAMPLE NUMBER USCSSYMBOLUNIFIED SOIL CLASSIFICATION SYSTEM (USCS)GROUP NAME GRAIN SIZE DISTRIBUTION TEST RESULTS PE R C E N T F I N E R B Y W E I G H T PE R C E N T C O A R S E R B Y W E I G H T SIZE OF MESH OPENING IN INCHES NO. OF MESH OPENINGS PER INCH, U.S. STANDARD 0.01 COBBLES COARSE GRAVEL GRAIN SIZE IN MILLIMETERS FINE COARSE 100 90 80 70 60 50 40 30 20 10 0 The sample did not meet test standard's minimumrequirements GRAVEL%SAND%FINES%TEST NOTE 12"#40 55 70 32 6 13 24 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 NATWC % 8.3 10.0 B-4 Page 1 of 1 SIEVE ANALYSIS HYDROMETER ANALYSIS Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the grain size distribution test results.ABBREVIATIONS: NAT WC = natural moisture content; RVW = reviewed by; STD = Standard; USCS = Unified Soil Classification System code; ~ = approximately (used when measured but not greater than 0.5%) 0 10 20 30 40 50 60 70 80 90 100 0.00124680.0124680.12468124681024681002 3"#200#4 #103/4"0.001 DEPTH(feet) MEDIUM TESTBY/RVW RXADJB RXADJB RXADJB TESTSTD D6913 D6913 D6913 B-5, S-3 B-5, S-5 B-5, S-6 Sieve analysis only - no Atterberg Limits:Group Name not estimated Sieve analysis only - no Atterberg Limits:Group Name not estimated Sieve analysis only - no Atterberg Limits:Group Name not estimated FINE SAND FINES: SILT OR CLAY GRAIN SIZE IN MILLIMETERS 7.5 12.5 15.0 EXPLORATION ANDSAMPLE NUMBER USCSSYMBOLUNIFIED SOIL CLASSIFICATION SYSTEM (USCS)GROUP NAME GRAIN SIZE DISTRIBUTION TEST RESULTS PE R C E N T F I N E R B Y W E I G H T PE R C E N T C O A R S E R B Y W E I G H T SIZE OF MESH OPENING IN INCHES NO. OF MESH OPENINGS PER INCH, U.S. STANDARD 0.01 COBBLES COARSE GRAVEL GRAIN SIZE IN MILLIMETERS FINE COARSE 100 90 80 70 60 50 40 30 20 10 0 The sample did not meet test standard's minimumrequirements The sample did not meet test standard's minimumrequirements The sample did not meet test standard's minimumrequirements GRAVEL%SAND%FINES%TEST NOTE 12"#40 45 38 34 43 57 62 12 5 5 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 NATWC % 9.0 9.7 9.6 B-5 Page 1 of 1 SIEVE ANALYSIS HYDROMETER ANALYSIS Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 The U-Line indicates the approximate upper boundarylimit for natural soils. The Unified Soil Classification System (USCS) group symbols listed belowrepresent the classification of the fine-grained portion of the soil. ML or OL Silt or Organic Silt = LL < 50 and below the A-Line MH or OH Elastic Silt or Organic Silt = LL > 50 and below the A-Line CL or OL Lean Clay or Organic Clay = LL < 50 and above the A-Line CH or OH Fat Clay or Organic Clay = LL > 50 and above the A-Line CL-ML Silty Clay = PI between 4 and 7 and in box shown below * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the Atterberg Limits test results.ABBREVIATIONS: LL = liquid limit; NAT MC = natural moisture content; n/a = test attempted; NP = nonplastic; PI = plasticity index; PL = plastic limit; STD = standard; RVW = reviewed by;USCS = Unified Soil Classification System symbol CL or OL 00 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 TEST NOTE SC ATTERBERG LIMITS TEST RESULTS PL A S T I C I T Y I N D E X , P I PL A S T I C I T Y I N D E X , P I UNIFIED SOIL CLASSIFICATIONSYSTEM (USCS) GROUP NAME USCSSYMBOL 27 16 CLAYEY SAND with GRAVEL B DEPTH(feet) 3.2 EXPLORATION ANDSAMPLE NUMBER 11 LL PL PI 10 20 30 40 50 60 B-2, S-1 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 16.0 NATMC %TESTBY/RVW D4318 TESTSTDFINES(%) 45 TDTDJB B-2 Page 1 of 1 LIQUID LIMIT, LL U-Lin e A-Lin e 4 7 16 CL-ML ML or OL MH or OH CH or OH Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 The U-Line indicates the approximate upper boundarylimit for natural soils. The Unified Soil Classification System (USCS) group symbols listed belowrepresent the classification of the fine-grained portion of the soil. ML or OL Silt or Organic Silt = LL < 50 and below the A-Line MH or OH Elastic Silt or Organic Silt = LL > 50 and below the A-Line CL or OL Lean Clay or Organic Clay = LL < 50 and above the A-Line CH or OH Fat Clay or Organic Clay = LL > 50 and above the A-Line CL-ML Silty Clay = PI between 4 and 7 and in box shown below * Where indicated by *, the USCS Group Name was based on visual-manual examination procedures (ASTM D2488) and the Atterberg Limits test results.ABBREVIATIONS: LL = liquid limit; NAT MC = natural moisture content; n/a = test attempted; NP = nonplastic; PI = plasticity index; PL = plastic limit; STD = standard; RVW = reviewed by;USCS = Unified Soil Classification System symbol CL or OL 00 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 TEST NOTE ATTERBERG LIMITS TEST RESULTS PL A S T I C I T Y I N D E X , P I PL A S T I C I T Y I N D E X , P I UNIFIED SOIL CLASSIFICATIONSYSTEM (USCS) GROUP NAME USCSSYMBOL 34 30 29 21 19 18 Atterberg Limits only - no sieveanalysis: Group Name not estimated Atterberg Limits only - no sieveanalysis: Group Name not estimated Atterberg Limits only - no sieveanalysis: Group Name not estimated DEPTH(feet) 2.5 10.0 15.0 EXPLORATION ANDSAMPLE NUMBER 13 11 11 LL PL PI 10 20 30 40 50 60 B-3, S-1 B-3, S-4 B-3, S-6 Kennydale Lakeline Sewer Improvements Renton, Washington SHANNON & WILSON | 400 NORTH 34TH STREET, SUITE 100 | SEATTLE, WASHINGTON 98103 | 206-632-8020 | www.shannonwilson.com Jo b # : 10 4 0 2 4 - 2 0 0 | T e m p l a t e V e r : 1 | F i l e : 1 0 4 0 2 4 . G P J | L i b r a r y : S W G I N T L I B R A R Y . G L B | D a t e : 11 / 1 7 / 2 4 20.2 25.8 21.1 NATMC %TESTBY/RVW D4318 D4318 D4318 TESTSTDFINES(%) MJKDJB MJKDJB MJKDJB B-3 Page 1 of 1 LIQUID LIMIT, LL U-Lin e A-Lin e 4 7 16 CL-ML ML or OL MH or OH CH or OH Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 C-i AP P E N D I X C : EX I S T I N G I N F O R M A T I O N B Y O T H E R S Appendix C: Existing Information by Others Appendix C Existing Information by Others CONTENTS Geotechnical Engineering Study, Proposed New Napoli Residence, 3111 Mountain View Avenue North, Renton, Washington, Geotech Consultants, Inc., November 2017. Geotechnical Engineering Study, Proposed New Residence, 3307 Mountain View Avenue North, Renton, Washington, Geotech Consultants, Inc., March 2020. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 CYEOTEC11 cONsui.Ta,rrTs, INC. DME Construction 410 Bellevue Way Southeast Suite 205 Bellevue, Washington 98004 Attention: Kathy Kilton via email: kathy@dmeconstruction.com Subject: Transmittal Letter — Geotechnical Engineering Study Proposed New Napoli Residence 3111 Mountain View Avenue North Renton, Washington Dear Ms. Kilton: 2401 10th Ave E Seattle, WashIhAton 98102 425) 747-5618 November 15, 2017 JN 17545 We are pleased to present this geotechnical engineering report for the proposed new Napoli residence to be constructed in Renton, Washington. The scope of our services consisted of exploring site surface and subsurface conditions, and then developing this report to provide recommendations for general earthwork, stormwater infiltration considerations, and design criteria for foundations and retaining walls. This work was authorized by your acceptance of our proposal, P-9859, dated August 7, 2017. The attached report contains a discussion of the study and our recommendations. Please contact us if there are any questions regarding this report, or for further assistance during the design and construction phases of this project. cc: Giovanni Napoli via email: gnapoli@kiddermathews.com ASM/MRM:mw Respectfully submitted, GEOTECH CONSULTANTS, INC. Adam S. Moyer Geotechnical Engineer GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 GEOTECHNICAL ENGINEERING STUDY Proposed New Napoli Residence 3111 Mountain View Avenue North Renton, Washington This report presents the findings and recommendations of our geotechnical engineering study for the site of the proposed new Napoli residence to be located in Renton. Development of the property is in the planning stage, and detailed plans were not available at the time of this report. Based on conversations with DME Construction, we understand the existing residence will be demolished and a new two-story single-family residence will be constructed in its place, albeit with a footprint that extends farther west than the existing house. We anticipate that the new residence may include at least a partial daylight basement. If the scope of the project changes from what we have described above, we should be provided with revised plans in order to determine if modifications to the recommendations and conclusions of this report are warranted. SITE CONDI TIONS SURFACE The Vicinity Map, Plate 1, illustrates the general location of the site along the southeast edge of Lake Washington in Renton. The long, narrow, subject site is generally rectangular in shape with 65 feet of frontage along Mountain View Avenue North on its eastern side and a depth of 373 to 393 feet along its northern and southern property lines respectively. However, only the eastern 175 feet of the property is above the surface of Lake Washington; this eastern half of the property will subsequently be referred to as the subject site. A one-story single-family residence is located near the center of subject site overlying a full basement that daylights to the west. A carport extends off the east side of the residence. Most of the ground surface between the residence and Mountain View Avenue North to the east is covered by a large concrete driveway; the concrete driveway wraps around the southern end of the residence, becoming a boat access ramp along the length of the southern property line extending down to Lake Washington. The remainder of the property is covered with a grass lawn. The eastern half of the subject site is essentially flat, matching the elevation of the adjacent right- of-way to the east. The ground surface of the western half of the site slopes moderately downwards towards Lake Washington to the west at a relatively uniform inclination. Based on the contour lines on King County's online GIS mapping tool, the change in elevation across the western half of the site is approximately 15 feet at an inclination of 17 percent down to the concrete bulkhead. The topography of the subject site is consistent with the neighboring parcels to the north and south along Lake Washington. There are no steep slopes on, or near, the site. Two-story single-family residences are located on the adjacent properties to the north and south. The residence to the north is offset 11 feet from the subject site and overlies a full basement that daylights to the west; an attached three -car garage extends off the eastern end of the residence near the elevation of Mountain View Avenue North with a significant offset from the subject site. The western third of the neighboring residence to the south has a full daylight basement at an 11 - foot offset from the shared property line with the subject site. However, based on our site GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) A 17545 November 15, 2017 Page 2 observations and information from King County Assessments Department, the eastern two thirds of the residence has a lowest finished floor near the upper eastern site grade, with an offset of 7 feet from the property line. SUBSURFACE The subsurface conditions were explored by drilling two test borings at the approximate locations shown on the Site Exploration Plan, Plate 2. Our exploration program was based on the proposed construction, anticipated subsurface conditions and those encountered during exploration, and the scope of work outlined in our proposal. The borings were drilled on October 20, 2017 using a limited -access track -mounted, hollow -stem auger drill. Samples were taken at approximate 2. 5- to 5 -foot intervals with a standard penetration sampler. This split -spoon sampler, which has a 2 -inch outside diameter, is driven into the soil with a 140 -pound hammer falling 30 inches. The number of blows required to advance the sampler a given distance is an indication of the soil density or consistency. A geotechnical engineer from our staff observed the drilling process, logged the test borings, and obtained representative samples of the soil encountered. The Test Boring Logs are attached as Plates 3 and 4. Soil Conditions Both borings conducted on the site encountered undisturbed dense silty sand with gravel at shallow depths below the existing ground surface. East of the existing residence, Boring 1 encountered the dense silty sand below a depth of 2. 5 feet and dense sand below a depth of 8 feet. The underlying sand became very dense below 20 feet and extended to the maximum -explored depth of 26.5 feet. Boring 2, located west of the existing residence, encountered medium -dense, weathered, silty sand with gravel at 2. 5 feet below a thin topsoil layer. The native silty sand became dense below 5 feet and very dense below a depth of 10 feet. The test boring was terminated in the very dense silty sand at a depth of 16.5 feet. No obstructions were revealed by our explorations. However, debris, buried utilities, and old foundation and slab elements are commonly encountered on sites that have had previous development. Groundwater Conditions No groundwater seepage was observed in our explorations. The test borings were conducted following a dry summer, and left open for only a short time period. It should be noted that groundwater levels vary seasonally with rainfall and other factors. The soil became wet below a depth of approximately 20 feet in Boring 1. This is indicative of a seasonal water table. We anticipate that groundwater could be found in more permeable soil layers as well as perched above the dense silty sand. The stratification lines on the logs represent the approximate boundaries between soil types at the exploration locations. The actual transition between soil types may be gradual, and subsurface conditions can vary between exploration locations. The logs provide specific subsurface information only at the locations tested. If a transition in soil type occurred between samples in the borings, the depth of the transition was interpreted. The relative densities and moisture descriptions indicated GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) JN 17545 November 15, 2017 Page 3 on the test boring logs are interpretive descriptions based on the conditions observed during drilling. CONCLUSIONS AND RECOMMENDATIONS GENERAL THIS SECTION CONTAINS A SUMMARY OF OUR STUDY AND FINDINGS FOR THE PURPOSES OF A GENERAL OVERVIEW ONLY. MORE SPECIFIC RECOMMENDATIONS AND CONCLUSIONS ARE CONTAINED IN THE REMAINDER OF THIS REPORT. ANY PARTY RELYING ON THIS REPORT SHOULD READ THE ENTIRE DOCUMENT. The test borings conducted for this study encountered dense, undisturbed, silty sand at depths of 2.5 to 5 feet below the -existing ground surface on the eastern and western sides of the subject site respectively. Conventional shallow foundations bearing on these dense native soils are well-suited to support the proposed residence. Depending on the final design, some minor overexcavations may be necessary along the western end of the proposed residence to reach the competent underlying dense soils. The onsite silty sand soils are very moisture -sensitive and can easily become disturbed and softened from foot and equipment traffic when wet; we recommend footing subgrade soils be covered with several inches of clean crushed rock immediately after the excavation is completed to prevent the subgrade soils from becoming softened and to maintain the bearing capacity of the soils. The silty nature of the onsite soils also makes them very difficult to adequately compact if they are even 2 to 3 percent above their optimum moisture content. Therefore, we recommend any structural fill placed beneath foundations consist of large -aggregate, clean, crushed rock such as 2 - inch railroad ballast or 2- to 4 -inch quarry spalls. The onsite sand could be used for structural fill behind foundation walls, provided it can be placed at or near its optimum moisture content; this will likely not be feasible during the wetter winter months. It may be necessary to backfill portion of the existing basement to support new foundations. If so, it must first be verified that competent bearing soils have been reached. The placement and compaction of any structural fill beneath foundations should occur under the guidance of the project geotechnical engineer. The proposed residence is in the early development stages and no plans were provided to us; however, we anticipate the residence may overlie a daylight basement. The depth of a new basement floor and its offsets from the northern and southern property lines will be a large factor in the construction of the residence. We recommend temporary open cut slopes be inclined no steeper than a 1: 1 (Horizontal:Vertical). If excavations cannot be maintained within the property lines, temporary excavation easements onto the neighboring properties will be required. If temporary easements cannot be obtained, temporary excavation shoring will be necessary. No un - shored excavations should extend below a 2:1 (H:V) line extended down from the base of the adjacent building footings. We can provide updated excavation and/or temporary excavation shoring recommendations once plans for the proposed residence have been developed. We anticipate that onsite infiltration of collected stormwater from impervious surfaces will be considered for the project. The silty sand revealed in our test borings has a very low permeability due to their high fines content and dense nature. As a result, there are no large or continuous pore spaces in the soil that can transmit water. This commonly results in groundwater becoming perched GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) A 17545 November 15, 2017 Page 4 above the dense underlying silty sand in the Puget Sound Area. Considering this, it is our professional opinion that onsite infiltration of stormwater is not feasible for the subject site. The erosion control measures needed during the site development will depend heavily on the weather conditions that are encountered during the site work. The location of the site on the shore of Lake Washington will make proper erosion control implementation important to prevent adverse impacts to the lake. However, we have been associated with numerous waterfront projects that have avoided siltation of the lake and surrounding properties by exercising care and being pro- active with the maintenance and potential upgrading of the erosion control system through the entire construction process. One of the most important considerations, particularly during wet weather, is to immediately cover any bare soil to prevent accumulated water or runoff from the work area from becoming silty in the first place. Silty water cannot be discharged to the lake. A wire -backed silt fence bedded in compost, not native soil or sand, should be erected as close as possible to the planned work area, and the existing vegetation between the silt fence and the lake left in place. Rocked construction access and staging areas should be established wherever trucks will have to drive off of pavement, in order reduce the amount of soil or mud carried off the property by trucks and equipment. It will also be important to cap any existing drain lines found running toward the lake until excavation is completed. This includes old septic lines. This will reduce the potential for silty water finding an old pipe and flowing into the lake. Covering the base of the excavation with a layer of clean gravel or rock is also prudent to reduce the amount of mud and silty water generated. Utilities reaching between the house and the lake should not be installed during rainy weather, and any disturbed area caused by the utility installation should be minimized by using small equipment. Cut slopes and soil stockpiles should be covered with plastic during wet weather. Soil stockpiles should be minimized. Following rough grading, it may be necessary to mulch or hydroseed bare areas that will not be immediately covered with landscaping or an impervious surface. The drainage and/or waterproofing recommendations presented in this report are intended only to prevent active seepage from flowing through concrete walls or slabs. Even in the absence of active seepage into and beneath structures, water vapor can migrate through walls, slabs, and floors from the surrounding soil, and can even be transmitted from slabs and foundation walls due to the concrete curing process. Water vapor also results from occupant uses, such as cooking and bathing. Excessive water vapor trapped within structures can result in a variety of undesirable conditions, including, but not limited to, moisture problems with flooring systems, excessively moist air within occupied areas, and the growth of molds, fungi, and other biological organisms that may be harmful to the health of the occupants. The designer or architect must consider the potential vapor sources and likely occupant uses, and provide sufficient ventilation, either passive or mechanical, to prevent a build up of excessive water vapor within the planned structure. Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this report are adequately addressed in the design. Such a plan review would be additional work beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, development, and geotechnical constraints that become more evident during the review process. As with any project that involves demolition of existing site buildings and/or extensive excavation and shoring, there is a potential risk of movement on surrounding properties. This can potentially translate into noticeable damage of surrounding on -grade elements, such as foundations and slabs. However, the demolition, shoring, and/or excavation work could just translate into perceived damage on adjacent properties. Unfortunately, it is becoming more and more common for adjacent property owners to make unsubstantiated damage claims on new projects that occur close to their GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) A 17545 November 15, 2017 Page 5 developed lots. Therefore, we recommend making an extensive photographic and visual survey of the project vicinity, prior to demolition activities, installing shoring, and/or commencing with the excavation. This documents the condition of buildings, pavements, and utilities in the immediate vicinity of the site in order to avoid, and protect the owner from, unsubstantiated damage claims by surrounding property owners. Additionally, any adjacent structures should be monitored during construction to detect soil movements. To monitor their performance, we recommend establishing a series of survey reference points to measure any horizontal deflections of the shoring system. Control points should be established at a distance well away from the walls and slopes, and deflections from the reference points should be measured throughout construction by survey methods. We recommend including this report, in its entirety, in the project contract documents. This report should also be provided to any future property owners so they will be aware of our findings and recommendations. SEISMIC CONSIDERATIONS In accordance with the International Building Code (IBC), the site class within 100 feet of the ground surface is best represented by Site Class Type C (Very Dense Soil and Soft Rock). As noted in the USGS website, the mapped spectral acceleration value for a 0. 2 second (SS) and 1.0 second period (Si) equals 1.45g and 0.55g, respectively. The IBC and ASCE 7 require that the potential for liquefaction (soil strength loss) be evaluated for the peak ground acceleration of the Maximum Considered Earthquake (MCE), which has a probability of occurring once in 2,475 years (2 percent probability of occurring in a 50 -year period). The soils beneath the site are not susceptible to seismic liquefaction under the ground motions of the MCE because of their dense nature and the absence of near -surface groundwater. CONVENTIONAL FO UNDA TIONS The proposed structure can be supported on conventional continuous and spread footings bearing on undisturbed, dense, native soil. We recommend that continuous and individual spread footings have minimum widths of 12 and 16 inches, respectively. Exterior footings should also be bottomed at least 18 inches below the lowest adjacent finish ground surface for protection against frost and erosion. The local building codes should be reviewed to determine if different footing widths or embedment depths are required. Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending upon site and equipment constraints, this may require removing the disturbed soil by hand. Depending on the final site grades, overexcavation may be required below the footings to expose competent native soil. Unless lean concrete is used to fill an overexcavated hole, the overexcavation must be at least as wide at the bottom as the sum of the depth of the overexcavation and the footing width. For example, an overexcavation extending 2 feet below the bottom of a 2 -foot -wide footing must be at least 4 feet wide at the base of the excavation. If lean concrete is used, the overexcavation need only extend 6 inches beyond the edges of the footing. A typical detail for overexcavation beneath footings is attached as Plate 5. An allowable bearing pressure of 3,000 pounds per square foot (psf) is appropriate for footings supported on competent native soil. A one-third increase in this design bearing pressure may be GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) JN 17545 November 15, 2017 Page 6 used when considering short-term wind or seismic loads. For the above design criteria, it is anticipated that the total post -construction settlement of footings founded on competent native soil will be about one inch, with differential settlements on the order of one half-inch in a distance of 50 feet along a continuous footing with a uniform load. Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the foundation. For the latter condition, the foundation must be either poured directly against relatively level, undisturbed soil or be surrounded by level, well -compacted fill. We recommend using the following ultimate values for the foundation's resistance to lateral loading: PARAMETERI ULTIMATE VALUE Coefficient of Friction 0.50 Passive Earth Pressure 300 pcf Where: pcf is Pounds per Cubic Foot, and Passive Earth Pressure is computed using the Equivalent Fluid Density. If the ground in front of a foundation is loose or sloping, the passive earth pressure given above will not be appropriate. We recommend maintaining a safety factor of at least 1.5 for the foundation's resistance to lateral loading, when using the above ultimate values. FOUNDATION AND RETAINING WALLS Retaining walls backfilled on only one side should be designed to resist the lateral earth pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain level backfill: PARAMETER Active Earth Pressure * 35 pcf Passive Earth Pressure 300 pcf Coefficient of Friction 0.50 Soil Unit Weight 130 pcf Where: pcf is Pounds per Cubic Foot, and Active and Passive Earth Pressures are computed using the Equivalent Fluid Pressures. For a restrained wall that cannot deflect at least 0.002 times its height, a uniform lateral pressure equal to 10 psf times the height of the wall should be added to the above active equivalent fluid pressure. - The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. The surcharge due to traffic loads behind a wall can typically be accounted GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) A 17545 November 15, 2017 Page 7 for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equal to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The values given above are to be used to design only permanent foundation and retaining walls that are to be backfilled, such as conventional walls constructed of reinforced concrete or masonry. It is not appropriate to use the above earth pressures and soil unit weight to back -calculate soil strength parameters for design of other types of retaining walls, such as soldier pile, reinforced earth, modular or soil nail walls. We can assist with design of these types of walls, if desired. The passive pressure given is appropriate only for a shear key poured directly against undisturbed native soil, or for the depth of level, well -compacted fill placed in front of a retaining or foundation wall. The values for friction and passive resistance are ultimate values and do not include a safety factor. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height from corners or bends in the walls. This is intended to reduce the amount of cracking that can occur where a wall is restrained by a corner. Wall Pressures Due to Seismic Forces The surcharge wall loads that could be imposed by the design earthquake can be modeled by adding a uniform lateral pressure to the above -recommended active pressure. The recommended surcharge pressure is 8H pounds per square foot (psf), where H is the design retention height of the wall. Using this increased pressure, the safety factor against sliding and overturning can be reduced to 1.2 for the seismic analysis. Retaininq Wall Backfill and Waterproofin_g Backfill placed behind retaining or foundation walls should be coarse, free -draining structural fill containing no organics. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be between 25 and 70 percent. If the native sand is used as backfill, a drainage composite similar to Miradrain 6000 should be placed against the backfilled retaining walls. The drainage composites should be hydraulically connected to the foundation drain system. Free -draining backfill or gravel should be used for the entire width of the backfill where seepage is encountered. For increased protection, drainage composites should be placed along cut slope faces, and the walls should be backfilled entirely with free -draining soil. The later section entitled Drainage Considerations should also be reviewed for recommendations related to subsurface drainage behind foundation and retaining walls. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. Also, subsurface drainage systems are not intended to handle large volumes of water from surface runoff. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. Water percolating through pervious surfaces (pavers, gravel, permeable pavement, etc.) must also be prevented from flowing toward walls or into the backfill zone. The compacted subgrade below pervious surfaces and any associated drainage layer should therefore be sloped away. Alternatively, a membrane and subsurface collection system could be provided below a pervious surface. GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) November 15, 2017 JN 17545 Page S It is critical that the wall backfill be placed in lifts and be properly compacted, in order for the above -recommended design earth pressures to be appropriate. The wall design criteria assume that the backfill will be well -compacted in lifts no thicker than 12 inches. The compaction of backfill near the walls should be accomplished with hand -operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaction. The section entitled General Earthwork and Structural Fill contains additional recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. The above recommendations are not intended to waterproof below -grade walls, or to prevent the formation of mold, mildew or fungi in interior spaces. Over time, the performance of subsurface drainage systems can degrade, subsurface groundwater flow patterns can change, and utilities can break or develop leaks. Therefore, waterproofing should be provided where future seepage through the walls is not acceptable. This typically includes limiting cold -joints and wall penetrations, and using bentonite panels or membranes on the outside of the walls. There are a variety of different waterproofing materials and systems, which should be installed by an experienced contractor familiar with the anticipated construction and subsurface conditions. Applying a thin coat of asphalt emulsion to the outside face of a wall is not considered waterproofing, and will only help to reduce moisture generated from water vapor or capillary action from seeping through the concrete. As with any project, adequate ventilation of basement and crawl space areas is important to prevent a buildup of water vapor that is commonly transmitted through concrete walls from the surrounding soil, even when seepage is not present. This is appropriate even when waterproofing is applied to the outside of foundation and retaining walls. We recommend that you contact an experienced envelope consultant if detailed recommendations or specifications related to waterproofing design, or minimizing the potential for infestations of mold and mildew are desired. The General, Slabs -On -Grade, and Drainage Considerations sections should be reviewed for additional recommendations related to the control of groundwater and excess water vapor for the anticipated construction. SLABS -ON -GRADE The building floors can be constructed as slabs -on -grade atop non-organic native soil, or on structural fill. The subgrade soil must be in a firm, non -yielding condition at the time of slab construction or underslab fill placement. Any soft areas encountered should be excavated and replaced with select, imported structural fill. Even where the exposed soils appear dry, water vapor will tend to naturally migrate upward through the soil to the new constructed space above it. This can affect moisture -sensitive flooring, cause imperfections or damage to the slab, or simply allow excessive water vapor into the space above the slab. All interior slabs -on -grade should be underlain by a capillary break drainage layer consisting of a minimum 4 -inch thickness of clean gravel or crushed rock that has a fines content percent passing the No. 200 sieve) of less than 3 percent and a sand content (percent passing the No. 4 sieve) of no more than 10 percent. Pea gravel or crushed rock are typically used for this layer. GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) A 17545 November 15, 2017 Page 9 As noted by the American Concrete Institute (ACI) in the Guides for Concrete Floor and Slab Structures, proper moisture protection is desirable immediately below any on -grade slab that will be covered by tile, wood, carpet, impermeable floor coverings, or any moisture -sensitive equipment or products. ACI also notes that vapor retarders such as 6 -mil plastic sheeting have been used in the past, but are now recommending a minimum 10 -mil thickness for better durability and long term performance. A vapor retarder is defined as a material with a permeance of less than 0.3 perms, as determined by ASTM E 96. It is possible that concrete admixtures may meet this specification, although the manufacturers of the admixtures should be consulted. Where vapor retarders are used under slabs, their edges should overlap by at least 6 inches and be sealed with adhesive tape. The sheeting should extend to the foundation walls for maximum vapor protection. If no potential for vapor passage through the slab is desired, a vapor barrier should be used. A vapor barrier, as defined by ACI, is a product with a water transmission rate of 0.01 perms when tested in accordance with ASTM E 96. Reinforced membranes having sealed overlaps can meet this requirement. We recommend that the contractor, the project materials engineer, and the owner discuss these issues and review recent ACI literature and ASTM E-1643 for installation guidelines and guidance on the use of the protection/blotter material. The General, Permanent Foundation and Retaining Walls, and Drainage Considerations sections should be reviewed for additional recommendations related to the control of groundwater and excess water vapor for the anticipated construction. EXCAVATIONS AND SLOPES Excavation slopes should not exceed the limits specified in local, state, and national government safety regulations. Temporary cuts to a depth of about 4 feet may be attempted vertically in unsaturated soil, if there are no indications of slope instability. However, vertical cuts should not be made near property boundaries, or existing utilities and structures. Based upon Washington Administrative Code (WAC) 296, Part N, the soil at the subject site would generally be classified as Type B. Therefore, temporary cut slopes greater than 4 feet in height should not be excavated at an inclination steeper than 1:1 (Horizontal:Vertical), extending continuously between the top and the bottom of a cut. The above -recommended temporary slope inclination is based on the conditions exposed in our explorations, and on what has been successful at other sites with similar soil conditions. It is possible that variations in soil and groundwater conditions will require modifications to the inclination at which temporary slopes can stand. Temporary cuts are those that will remain unsupported for a relatively short duration to allow for the construction of foundations, retaining walls, or utilities. Temporary cut slopes should be protected with plastic sheeting during wet weather. It is also important that surface runoff be directed away from the top of temporary slope cuts. Cut slopes should also be backfilled or retained as soon as possible to reduce the potential for instability. Please note that sand or loose soil can cave suddenly and without warning. Excavation, foundation, and utility contractors should be made especially aware of this potential danger. These recommendations may need to be modified if the area near the potential cuts has been disturbed in the past by utility installation, or if settlement -sensitive utilities are located nearby. All permanent cuts into native soil should be inclined no steeper than 2:1 (H:V). Fill slopes should not be constructed with an inclination greater than 2.5:1 (H:V). To reduce the potential for shallow sloughing, fill must be compacted to the face of these slopes. This can be accomplished by GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) JN 17545 November 15, 2017 Page 10 overbuilding the compacted fill and then trimming it back to its final inclination. Adequate compaction of the slope face is important for long-term stability and is necessary to prevent excessive settlement of patios, slabs, foundations, or other improvements that may be placed near the edge of the slope. Water should not be allowed to flow uncontrolled over the top of any temporary or permanent slope. All permanently exposed slopes should be seeded with an appropriate species of vegetation to reduce erosion and improve the stability of the surficial layer of soil. DRAINAGE CONSIDERATIONS Footing drains should be used where: (1) Crawl spaces or basements will be below a structure; (2) A slab is below the outside grade; or, (3) The outside grade does not slope downward from a building. Drains should also be placed at the base of all earth -retaining walls. These drains should be surrounded by at least 6 inches of 1 -inch -minus, washed rock that is encircled with non -woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a perforated pipe invert should be at least 6 inches below the bottom of a slab floor or the level of a crawl space. The discharge pipe for subsurface drains should be sloped for flow to the outlet point. Roof and surface water drains must not discharge into the foundation drain system. A typical footing drain detail is attached to this report as Plate 6. For the best long-term performance, perforated PVC pipe is recommended for all subsurface drains. As a minimum, a vapor retarder, as defined in the Slabs -On -Grade section, should be provided in any crawl space area to limit the transmission of water vapor from the underlying soils. Crawl space grades are sometimes left near the elevation of the bottom of the footings. As a result, an outlet drain is recommended for all crawl spaces to prevent an accumulation of any water that may bypass the footing drains. Providing even a few inches of free draining gravel underneath the vapor retarder limits the potential for seepage to build up on top of the vapor retarder. No groundwater was observed during our field work. If seepage is encountered in an excavation, it should be drained from the site by directing it through drainage ditches, perforated pipe, or French drains, or by pumping it from sumps interconnected by shallow connector trenches at the bottom of the excavation. The excavation and site should be graded so that surface water is directed off the site and away from the tops of slopes. Water should not be allowed to stand in any area where foundations, slabs, or pavements are to be constructed. Final site grading in areas adjacent to a building should slope away at least 2 percent, except where the area is paved. Surface drains should be provided where necessary to prevent ponding of water behind foundation or retaining walls. A discussion of grading and drainage related to pervious surfaces near walls and structures is contained in the Foundation and Retaining Walls section. GENERAL EARTHWORK AND STRUCTURAL FILL All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and other deleterious material. It is important that existing foundations be removed before site development. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) JN 17545 November 15, 2017 Page 11 Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compacted dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. Fills placed on sloping ground should be keyed into the dense native soils. This is typically accomplished by placing and compacting the structural fill on level benches that are cut into the competent soils. The allowable thickness of the fill lift will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lift. The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not sufficiently compacted, it can be recompacted before another lift is placed. This eliminates the need to remove the fill to achieve the required compaction. The following table presents recommended relative compactions for structural fill: LOCATION s i PLACEMENT COMPACTION Beneath slabs or 95% walkways Filled slopes and behind 90% retaining walls 95% for upper 12 inches of Beneath pavements subgrade; 90% below that level Where: Minimum Relative Compaction is the ratio, expressed in percentages, of the compacted dry density to the maximum dry density, as determined in accordance with ASTM Test Designation D 1557-91 (Modified Proctor). Use of On -Site Soil If grading activities take place during wet weather, or when the silty, on-site soil is wet, site preparation costs may be higher because of delays due to rain and the potential need to import granular fill. The on-site soil is generally silty and therefore moisture sensitive. Grading operations will be difficult during wet weather, or when the moisture content of this soil exceeds the optimum moisture content. The moisture content of the silty, on-site soil must be at, or near, the optimum moisture content, as the soil cannot be consistently compacted to the required density when the moisture content is significantly greater than optimum. The moisture content of the on-site soil was generally above the estimated optimum moisture content at the time of our explorations. The on-site sand and silty sand underlying the topsoil could be used as structural fill, if grading operations are conducted during hot, dry weather, when drying the wetter soil by aeration is possible. During excessively dry weather, however, it may be necessary to add water to achieve the optimum moisture content. Moisture -sensitive soil may also be susceptible to excessive softening and "pumping" from construction equipment, or even foot traffic, when the moisture content is greater than the GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) November 15, 2017 JN 17545 Page 12 optimum moisture content. It may be beneficial to protect subgrades with a layer of imported sand or crushed rock to limit disturbance from traffic. The General section should be reviewed for considerations related to the reuse of on-site soils. Structural fill that will be placed in wet weather should consist of a coarse, granular soil with a silt or clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve should be measured from that portion of soil passing the three -quarter -inch sieve. LIMITATIONS The conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our exploration and assume that the soil and groundwater conditions encountered in the test borings are representative of subsurface conditions on the site. If the subsurface conditions encountered during construction are significantly different from those observed in our explorations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking samples in test borings. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expenditures to attain a properly constructed project. It is recommended that the owner consider providing a contingency fund to accommodate such potential extra costs and risks. This is a standard recommendation for all projects. This report has been prepared for the exclusive use of DME Construction and its representatives, for specific application to this project and site. Our conclusions and recommendations are professional opinions derived in accordance with our understanding of current local standards of practice, and within the scope of our services. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. Our services also do not include assessing or minimizing the potential for biological hazards, such as mold, bacteria, mildew and fungi in either the existing or proposed site development. ADDITIONAL SERVICES In addition to reviewing the final plans, Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and observation services during construction. This is to confirm that subsurface conditions are consistent with those indicated by our exploration, to evaluate whether earthwork and foundation construction activities comply with the general intent of the recommendations presented in this report, and to provide suggestions for design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. However, our work would not include the supervision or direction of the actual work of the contractor and its employees or agents. Also, job and site safety, and dimensional measurements, will be the responsibility of the contractor. During the construction 'phase, we will provide geotechnical observation and testing services when requested by you or your representatives. Please be aware that we can only document site work we actually observe. It is still the responsibility of your contractor or on-site construction team to verify that our recommendations are being followed, whether we are present at the site or not. GEOTECH CONSULTANTS, INC. Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 DME Construction (Napoli Residence) November 15, 2017 The following plates are attached to complete this report: Plate 1 Vicinity Map Plate 2 Site Exploration Plan Plates 3 - 4 Test Boring Logs Plate 5 Typical Footing Overexcavation Plate 6 Typical Footing Drain Detail JN 17545 Page 13 We appreciate the opportunity to be of service on this project. Please contact us if you have any questions, or if we can be of further assistance. ASM/MRM:mw Respectfully submitted, GEOTECH CONSULTANTS, INC. Ala m S. Moyer Geotechnical Engineer R. Ale S pF WASJla, 'cP vISTF, SsjONAL V, S 17 Marc R. McGinnis, P.E. Principal GEOTECH CONSULTANTS, INC. 1% Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Source: Microsoft MapPoint, 2013) VICINITY MAP 3111 Mountain View Avenue North Renton, Washington Job No: Date: Plate: 17545 Nov. 2017 1 ifaWr i E 4 j} I Lh L 5 '- Vi£ lk F Source: Microsoft MapPoint, 2013) VICINITY MAP 3111 Mountain View Avenue North Renton, Washington Job No: Date: Plate: 17545 Nov. 2017 1 i r 2 t S' f y 4 r g Source: Microsoft MapPoint, 2013) VICINITY MAP 3111 Mountain View Avenue North Renton, Washington Job No: Date: Plate: 17545 Nov. 2017 1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Legend: Test Boring Location GEOTECH CONSULTANTS, INC. SITE EXPLORATION PLAN 3111 Mountain View Avenue North Renton, Washington Job No: Date: I Plate: 17545 Nov. 2017 No Scale 2 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 5 10 15 20 25 Kill C-1 00 CO 44 47 1 33 I 53 65 BORING 1 Description Gray -brown silty SAND with gravel, fine-grained, moist, dense4 Fs -ml: 2 Test boring was terminated at 26.5 feet on October 20, 2017. No groundwater was encountered during drilling. GEOTECH CONSULTANTS,, INC. TEST BORING LOG 3111 Mountain View Avenue North Renton, Washington Job Date: Logged by: I Plate: j17545Nov. 2017 ASM 3 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 10 15 20 25 K%] BORING 2 Description GEOTECH CONSULTANTS, INC. TEST BORING LOG 3111 Mountain View Avenue North Renton, Washington Job Date:Logged by: Plate: 17545 Nov. 2017 ASM 4 ad, Brown silty SAND with gravel and occasional roots, fine to medium -grain t moist to dry, medium -dense 7/4" 1 stopped driving sampler due to obstruction 41 2 k€€ becomes gray -brown, fine-grained, dense sM1': 3 64 3 becomes very dense 71 4 EEE E iE€E E Test boring was terminated at 16.5 feet on October 20, 2017. No groundwater was encountered during drilling. GEOTECH CONSULTANTS, INC. TEST BORING LOG 3111 Mountain View Avenue North Renton, Washington Job Date:Logged by: Plate: 17545 Nov. 2017 ASM 4 ad, Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Unsuitable Soils 0.o.C'' a°° O C°, :O°°° 0oD0.0°'CO°0c 0,° ao,' O° O'0 ° o d00ooooD?'C6% oaoo0cC0 > o, .0 o, .D61 o .0. o 0 D °° D° o D ° a..+_ x.0°.Q, 00 op°•0p op°•o 00' ciD°•o"O o0°'0 o0D°•o ° oD o oa C'o 0 oQ 0'0 oQ 0'co0'0 0 oa D'o o -oJ D'co'° q o°°a'° q o°°o'° o °o'^ q o°°a°a ^ q o00 . o> •r7 . o. 'c'O . o, ° . > o• ° .DO •`O ° o, ° o a° 0 .o CI'0 ooo°Width of 'overexcavation00 'O,,°,:O D O° n a v n° v O o.nv 0'0 ° D Structural Fill (refer to report for gradation and compaction requirements). See Note 2 for condition where lean concrete is used to backfill the overexcavation. Suitable Bearing Soil (Refer to report for description) verify by Geotechnical Engineer prior to placing Structural Fill. pIIFF- Width of Overexcavation = Footing Width (FW) + Depth of Overexcavation NOTES: 1. Refer to report text for additional overexcavation, foundation, and structural fill considerations. 2. Where lean concrete (minimum 1- 1/2 sacks of cement per cubic yard) is used to backfill the overexcavation, the overexcavation must extend only 6 inches beyond the edges of the footing. GEOTECH CONSULTANTS, INC. TYPICAL FOOTING OVEREXCAVATION 3111 Mountain View Avenue North Renton, Washington Job No: Date: Plate: 17545 Nov. 2017 1 1 5 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Slope backfill away from foundation. Provide surface drains where necessary. Backfill See text for requirements) Washed Rock 7/8" min. size) 4" min. Nonwoven Geotextile Filter Fabric 0 0 0 0 0 T00O""oOo 0 0 0 0O0000 oOoOo Oo0o 0 ' O — o_ a Tightline Roof Drain Do not connect to footing drain) Possible Slab aQ." p •, p •Q a "° p . ° "° p ,Q o p .a a p ,Q ° "° p ,Q o,°°' o p o.° ° o odo0'o oppoQ 0'0 0 Qom 0'0 0 o/J 0'0 o pp0Q 0a 0'0 0 0 0 O o a 0 o O p O o o O.O. 0 J .0 0 0 000OOOOOpD .o .p •o o .o nDnn• n III Illldllll 4" Perforated Hard PVC Pipe Invert at least 6 inches below slab or crawl space. Slope to drain to appropriate outfall. Place holes downward.) Vapor Retarder/Barrier and Capillary Break/Drainage Layer Refer to Report text) NOTES: 1) In crawl spaces, provide an outlet drain to prevent buildup of water that bypasses the perimeter footing drains. 2) Refer to report text for additional drainage, waterproofing, and slab considerations. GEOTECH CONSULTAN'T'S, INC. FOOTING DRAIN DETAIL 3111 Mountain View Avenue North Renton, Washington Job No: Date: Plate: 17545 Nov. 2017 1 1 6 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 D-i AP P E N D I X D : S L O P E S T A B I L I T Y A N A L Y S I S R E S U L T S Appendix D: Slope Stability Analysis Results Appendix D Slope Stability Analysis Results Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 2.2 Distance -10 0 10 20 30 40 50 60 El e v a t i o n 30 40 50 60 SHANNON & WILSON, INC.Geotechnical and Environmental Consultants December 2024 104024-200 Kennydale Lakeline Sewer Improvements Renton, Washington SLOPE STABILITY ANALYSIS Static Undrained P: \ S E A \ 1 0 4 0 0 0 s \ 1 0 4 0 2 4 R e n t o n K e n n y d a l e L a k e l i n e \ - 2 0 0 G e o t e c h n i c a l\A n a l y s i s \ S l o p e s t a b i l i t y \ \ K e n n y d a l e L a k e l i n e _ B - 3 . g s z Notes:1. FS = Factor of Safety2. Analysis Type: SLOPE/W3. FS Method: Morgenstern-Price4. Search Method: Entry and Exit5. Minimum Slip Surface Depth: 0.1 feet Color Name Slope Stability Material Model Unit Weight(pcf) Effective Cohesion(psf) EffectiveFriction Angle (°) PiezometricSurface CL (Qvrl) Undrained Mohr-Coulomb 105 1,000 0 1 CL (Qvrl) Undrained (2)Mohr-Coulomb 110 1,200 0 1 SM (Qvro) Mohr-Coulomb 115 0 28 1 SM (Qvro) (2) Mohr-Coulomb 120 0 34 1 SM (Qvt) Mohr-Coulomb 130 4,000 0 1 SP-SM (Qvro) Mohr-Coulomb 115 0 30 1 East West FS: FIG. D-1 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 0.8 Distance -10 0 10 20 30 40 50 60 El e v a t i o n 30 40 50 60 SHANNON & WILSON, INC.Geotechnical and Environmental Consultants December 2024 104024-200 Kennydale Lakeline Sewer Improvements Renton, Washington SLOPE STABILITY ANALYSIS Static Drained P: \ S E A \ 1 0 4 0 0 0 s \ 1 0 4 0 2 4 R e n t o n K e n n y d a l e L a k e l i n e \ - 2 0 0 G e o t e c h n i c a l\A n a l y s i s \ S l o p e s t a b i l i t y \ \ K e n n y d a l e L a k e l i n e _ B - 3 . g s z Notes:1. FS = Factor of Safety2. Analysis Type: SLOPE/W3. FS Method: Morgenstern-Price4. Search Method: Entry and Exit5. Minimum Slip Surface Depth: 0.1 feet Color Name Slope Stability Material Model Unit Weight(pcf) Effective Cohesion(psf) EffectiveFriction Angle (°) PiezometricSurface CL (Qvrl) Drained Mohr-Coulomb 105 0 25 1 CL (Qvrl) Drained (2)Mohr-Coulomb 110 0 27 1 SM (Qvro) Mohr-Coulomb 115 0 28 1 SM (Qvro) (2) Mohr-Coulomb 120 0 34 1 SM (Qvt) Mohr-Coulomb 130 4,000 0 1 SP-SM (Qvro) Mohr-Coulomb 115 0 30 1 East West FS: FIG. D-2 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 1.6 Distance -10 0 10 20 30 40 50 60 El e v a t i o n 30 40 50 60 SHANNON & WILSON, INC.Geotechnical and Environmental Consultants 104024-200 Kennydale Lakeline Sewer Improvements Renton, Washington SLOPE STABILITY ANALYSIS Pseudo Static Undrained December 2024 P: \ S E A \ 1 0 4 0 0 0 s \ 1 0 4 0 2 4 R e n t o n K e n n y d a l e L a k e l i n e \ - 2 0 0 G e o t e c h n i c a l\A n a l y s i s \ S l o p e s t a b i l i t y \ \ K e n n y d a l e L a k e l i n e _ B - 3 . g s z Notes:1. FS = Factor of Safety2. Analysis Type: SLOPE/W3. FS Method: Morgenstern-Price4. Search Method: Entry and Exit5. Minimum Slip Surface Depth: 0.1 feet Color Name Slope Stability Material Model Unit Weight(pcf) Effective Cohesion(psf) EffectiveFriction Angle (°) PiezometricSurface CL (Qvrl) Undrained Mohr-Coulomb 105 1,000 0 1 CL (Qvrl) Undrained (2)Mohr-Coulomb 110 1,200 0 1 SM (Qvro) Mohr-Coulomb 115 0 28 1 SM (Qvro) (2) Mohr-Coulomb 120 0 34 1 SM (Qvt) Mohr-Coulomb 130 4,000 0 1 SP-SM (Qvro) Mohr-Coulomb 115 0 30 1 East West FS: FIG. D-3 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 1.5 Distance -10 0 10 20 30 40 50 60 El e v a t i o n 30 40 50 60 SHANNON & WILSON, INC.Geotechnical and Environmental Consultants 104024-200 Kennydale Lakeline Sewer Improvements Renton, Washington SLOPE STABILITY ANALYSIS Soil Nail - Static Drained December 2024 P: \ S E A \ 1 0 4 0 0 0 s \ 1 0 4 0 2 4 R e n t o n K e n n y d a l e L a k e l i n e \ - 2 0 0 G e o t e c h n i c a l\A n a l y s i s \ S l o p e s t a b i l i t y \ \ K e n n y d a l e L a k e l i n e _ B - 3 . g s z Notes:1. FS = Factor of Safety2. Analysis Type: SLOPE/W3. FS Method: Morgenstern-Price4. Search Method: Entry and Exit5. Minimum Slip Surface Depth: 0.1 feet Color Name Slope Stability Material Model Unit Weight(pcf) Effective Cohesion(psf) EffectiveFriction Angle (°) PiezometricSurface CL (Qvrl) Drained Mohr-Coulomb 105 0 25 1 CL (Qvrl) Drained (2)Mohr-Coulomb 110 0 27 1 SM (Qvro) Mohr-Coulomb 115 0 28 1 SM (Qvro) (2) Mohr-Coulomb 120 0 34 1 SM (Qvt) Mohr-Coulomb 130 4,000 0 1 SP-SM (Qvro) Mohr-Coulomb 115 0 30 1 East West FS: Color Name Type Pullout Resistance (psf) Pullout Resistance Reduction Factor Tensile Capacity (lbf) Tensile Capacity Reduction Factor Shear Force (lbf)F of S Dependent Force Distribution Bond Diameter (ft) Out-of-Plane Spacing (ft)Face Anchorage Factored Pullout Resistance Factored Tensile Capacity Spiral Nail Nail 864 2 120,000 2 0 No Concentrated 0.208 5 Yes 56.458 lbf/ft/ft 12,000 lbf/ft Color ID Assigned Reinforcement Length(ft)Pullout Force (lbf)ShearForce(lbf) Governing Component 1 Spiral Nail 20 513.05 0 Pullout Resistance 2 Spiral Nail 20 440.61 0 Pullout Resistance 3 Spiral Nail 20 361.44 0 Pullout Resistance 4 Spiral Nail 20 309.65 0 Pullout Resistance FIG. D-4 Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 II-i IM P O R T A N T I N F O R M A T I O N Important Information Important Information About Your Geotechnical Report Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 II-1 IM P O R T A N T I N F O R M A T I O N CONSULTING SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND FOR SPECIFIC CLIENTS. Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your consultant prepared your report expressly for you and expressly for the purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the consultant. THE CONSULTANT'S REPORT IS BASED ON PROJECT-SPECIFIC FACTORS. A geotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set of project-specific factors. Depending on the project, these may include: the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the additional risk created by scope-of- service limitations imposed by the client. To help avoid costly problems, ask the consultant to evaluate how any factors that change subsequent to the date of the report may affect the recommendations. Unless your consultant indicates otherwise, your report should not be used: (1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered on or near the site); (2) when the size, elevation, or configuration of the proposed project is altered; (3) when the location or orientation of the proposed project is modified; (4) when there is a change of ownership; or (5) for application to an adjacent site. Consultants cannot accept responsibility for problems that may occur if they are not consulted after factors which were considered in the development of the report have changed. SUBSURFACE CONDITIONS CAN CHANGE. Subsurface conditions may be affected as a result of natural processes or human activity. Because a geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration, construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the consultant to advise if additional tests are desirable before construction starts; for example, groundwater conditions commonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/environmental report. The consultant should be kept apprised of any such events and should be consulted to determine if additional tests are necessary. MOST RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS. Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant, who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 II-2 IM P O R T A N T I N F O R M A T I O N and your consultant can work together to help reduce their impacts. Retaining your consultant to observe subsurface construction operations can be particularly beneficial in this respect. A REPORT'S CONCLUSIONS ARE PRELIMINARY. The conclusions contained in your consultant's report are preliminary because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Actual subsurface conditions can be discerned only during earthwork; therefore, you should retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations. The consultant who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction. THE CONSULTANT'S REPORT IS SUBJECT TO MISINTERPRETATION. Costly problems can occur when other design professionals develop their plans based on misinterpretation of a geotechnical/environmental report. To help avoid these problems, the consultant should be retained to work with other project design professionals to explain relevant geotechnical, geological, hydrogeological, and environmental findings, and to review the adequacy of their plans and specifications relative to these issues. BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE REPORT. Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data. Only final boring logs and data are customarily included in geotechnical/environmental reports. These final logs should not, under any circumstances, be redrawn for inclusion in architectural or other design drawings, because drafters may commit errors or omissions in the transfer process. To reduce the likelihood of boring log or monitoring well misinterpretation, contractors should be given ready access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If access is provided only to the report prepared for you, you should advise contractors of the report's limitations, assuming that a contractor was not one of the specific persons for whom the report was prepared, and that developing construction cost estimates was not one of the specific purposes for which it was prepared. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with your consultant and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems and the adversarial attitudes that aggravate them to a disproportionate scale. READ RESPONSIBILITY CLAUSES CLOSELY. Because geotechnical/environmental engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124 Kennydale Lakeline Sewer Improvements DRAFT Geotechnical Engineering Report 104024-200 December 6, 2024 II-3 IM P O R T A N T I N F O R M A T I O N being lodged against consultants. To help prevent this problem, consultants have developed a number of clauses for use in their contracts, reports, and other documents. These responsibility clauses are not exculpatory clauses designed to transfer the consultant's liabilities to other parties; rather, they are definitive clauses that identify where the consultant's responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions. The preceding paragraphs are based on information provided by theASFE/Association of Engineering Firms Practicing in the Geosciences, Silver Spring, Maryland Docusign Envelope ID: A6950DB9-F338-45C7-991A-0D2425171124