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Home My WebLink About16055-R-GEOT-AES-2012-09-28 - SN Geotechnical Engineering Associated Earth Sciences, Inc. Serving the Pacific Northwest Since 1981 Subsurface Exploration, Geologic Hazard, and Limited Geotechnical Engineering Report Water Resources TIFFANY PARK SITE Renton, Washington Prepared for Environmental _Assessments and Remediation Sustainable Development Services . Geologic .Assessments Renton School District #403 Project No. KE120359A September 28, 2012 Associated Earth Sciences, Inc. Serving the Pacific Northwest Since 1981 September 28, 2012 Project No. KE120359A Renton School District #403 Facility Operations and Maintenance 7812 South 124th Street Seattle, Washington 98178 Attention: Mr. Rick Stracke Subject: Subsurface Exploration, Geologic Hazard, and Limited Geotechnical Engineering Report Tiffany Park Site Renton, Washington Dear Mr. Stracke: We are pleased to present the enclosed copies of the referenced report. This report summarizes the results of our subsurface exploration, geologic hazard, and limited geotechnical engineering studies. This report is based on a site topographic survey by AHBL dated February 8, 2008. This report is intended to provide a general geotechnical feasibility analysis of the site. This report is not intended to be used as the sole geotechnical input for any site development proposal, and is not intended to satisfy City of Renton requirements for a Special Study as outlined in Renton Municipal Code Section 4-3-050 J2. We have enjoyed working with you on this study and are confident that the recommendations presented in this report will aid in the successful completion of your project. If you should have any questions, or if we can be of additional help to you, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington K rt D. Merriman, P.E. Senior Principal Engineer KDM/pald KE120359A4 Projects120120359 KEMP Kirkland Everett Tacoma 425-827-7701 425-259-0522 253-722-2992 www.aesgeo.com SUBSURFACE EXPLORATION, GEOLOGIC HAZARD, AND LIMITED GEOTECHNICAL ENGINEERING REPORT TIFFANY PARK SITE Renton, Washington Prepared for: Renton School District #403 Facility Operations and Maintenance 7812 South 124th Street Seattle, Washington 98178 Prepared by: Associated Earth Sciences, Inc. 911 5th Avenue, Suite 100 Kirkland, Washington 98033 425-827-7701 Fax: 425-827-5424 September 28, 2012 Project No. KE120359A Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Project and Site Conditions I. PROJECT AND SITE CONDITIONS 1.0 INTRODUCTION This report presents the results of our subsurface exploration, geologic hazard, and limited geotechnical engineering study for the subject site. The site location is shown on the "Vicinity Map," Figure 1. The approximate locations of explorations completed for this study, along with existing site features, are shown on the "Site and Exploration Plan," Figure 2. This report is based on a topographic survey sheet that was used as a basis for Figure 2. This report should be reviewed and revised as appropriate to support any specific development proposal, and is not intended to satisfy City of Renton requirements for a Special Study as outlined in Renton Municipal Code (RMC) Section 4-3-050 J2. 1.1 Purpose and Scope The purpose of this study was to provide subsurface data to be used to characterize the general geotechnical engineering properties of the site. Our study included a review of selected geologic literature, excavating exploration pits, and performing geologic studies to assess the type, thickness, distribution, and physical properties of the subsurface sediments and shallow ground water. Geotechnical engineering studies were completed to formulate our preliminary recommendations for site preparation, site grading, construction, and drainage. This report summarizes our current fieldwork and offers an overview of geotechnical characteristics of the site. We recommend that we be allowed to review and revise this report before it is used to support any specific development plan. 1.2 Authorization This report has been prepared for the exclusive use of the Renton School District and their agents for specific application to this project. Our work was performed in accordance with our scope of work and cost proposal dated August 28, 2012. We were authorized to proceed with this phase of work by means of a consultant agreement. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering and engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pc/ld - KE120359A4 - Projects120120359IKEIWP Page 1 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Project and Site Conditions 2.0 PROJECT AND SITE DESCRIPTION No specific development plan has been formulated for the site. We understand that this study may be used to assess general geotechnical feasibility of potential future uses of the property. The site is relatively flat, and we anticipate that likely development proposals might include construction of low rise structures, paving for vehicle access, and buried utilities. We anticipate that these types of structures would be constructed relatively close to existing grades without the need for deep excavations or thick structural fills. The project includes four tax parcels, with a total combined area of slightly less than 22 acres. The site slopes down to the west with typically gentle slope inclinations and has a total vertical relief on the order of 50 feet. The site contains areas that meet City of Renton definitions for Geotechnical Critical Areas. Critical areas issues are discussed in detail later in this report. At the time of our reconnaissance, the site was covered with mature trees and moderate undergrowth. A series of pedestrian trails was present on-site. 3.0 SUBSURFACE EXPLORATION Our field study included excavation of 12 exploration pits with a tracked excavator. The locations of the exploration pits were estimated based on measurements with hand-held tools from existing site features shown on the previously referenced site survey. The locations of these explorations should therefore be considered approximate. The exploration logs are presented in the Appendix. The various types of sediments, as well as the depths where characteristics of the sediments changed, are indicated on the exploration logs presented in the Appendix. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. The conclusions and recommendations presented in this report are based on the explorations completed for this study. The number, locations, and depths of our explorations were completed within site and budgetary constraints. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pc/ld - KE120359A4 - Projects120120359IKEIWP Page 2 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Project and Site Conditions 3.1 Exploration Pits The exploration pits were excavated using a tracked excavator. The pits permitted direct, visual observation of subsurface conditions. Materials encountered in the exploration pits were studied and classified in the field by a geologist from our firm. All exploration pits were backfilled after examination and logging. Selected samples were then transported to our laboratory for further visual classification as needed. 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field explorations accomplished for this study, visual reconnaissance of the site, and review of selected geologic literature. The general distribution of geologic units is shown on the field logs. The explorations generally encountered native materials consisting of dense lodgement till sediments. Two exploration pits on the northwest part of the site encountered zones of granular sediments with low silt content within the lodgement till which was interpreted to represent lodgement till/advance outwash transitional sediments. Our interpretations of subsurface conditions are generally consistent with the conditions shown on a published geologic map of the area. We reviewed the Geologic Map of King County, Washington, by Derek B. Booth, Kathy A. Troost, and Aaron P. Wisher, 2006. The referenced map indicates that the site is underlain by lodgement till sediments. 4.1 Stratigraphy Grass/Topsoil A surficial layer of organic topsoil was encountered at the location of each of the exploration pits. This organic layer ranged from approximately 1 to 1.9 feet in thickness. Observed topsoil thickness is shown on the attached subsurface exploration logs. Due to their high organic content, these materials are not considered suitable for foundation, roadway, or slab- on-grade floor support, or for use in a structural fill. Vashon Lodgement Till Exploration pits encountered typically medium dense grading to very dense, silty sand with gravel, cobbles, and boulders interpreted as Vashon lodgement till. The lodgement till observed in our explorations graded from medium dense and brown in the weathered zone near the surface to gray to gray-brown at depth. Lodgement till was deposited at the base of an active continental glacier and was subsequently compacted by the weight of the overlying glacial ice. Lodgement till typically possesses high-strength and low-compressibility attributes September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pc/ld - KE120359A4 - Projects120120359IKEIWP Page 3 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Project and Site Conditions that are favorable for support of foundations, floor slabs, and paving, with proper preparation. Lodgement till is silty and moisture-sensitive. In the presence of moisture contents above the optimum moisture content for compaction purposes, lodgement till can be easily disturbed by vehicles and earthwork equipment. Careful management of moisture-sensitive soils, as recommended in this report, will be needed to reduce the potential for disturbance of wet lodgement till soils and costs associated with repairing disturbed soils. 4.2 Hydrology Weak ground water seepage was observed in exploration pit EP-6 below a depth of 8 feet. Sites underlain by lodgement till sediments commonly develop a seasonal perched ground water condition where surface water infiltrates into shallow weathered sediments, then encounters dense silty unweathered sediments that inhibit further downward infiltration. Ground water then becomes "perched" and tends to move laterally above the less permeable subsurface sediments. Though we did not observe perched ground water in explorations completed for this study, we anticipate that perched ground water conditions are likely to develop seasonally at this site. The previously referenced topographic survey depicts two possible wetlands on-site that were identified and surveyed by others. Based on subsurface data summarized in this report, it appears likely that these wetlands formed in closed depressions underlain by relatively low-permeability lodgement till sediments. 4.3 Infiltration Feasibility The site is underlain at shallow depths by lodgement till sediments that are not a suitable infiltration receptor. Deeper infiltration strategies that rely on deep injection wells or pit drains might be feasible at this site. Shallow explorations completed for this limited study were not intended to determine the feasibility of deep infiltration strategies. September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pcfid - KE120359A4 - Projects1201203591KEIWP Page 4 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations II. GEOLOGIC HAZARDS AND MITIGATIONS The following discussion of potential geologic hazards is based on the geologic, slope, and shallow ground water conditions as observed and discussed herein. References to mapped critical areas are based on City of Renton Geographical Information System (GIS) mapping accessed on line. City code makes reference to critical areas maps. We have relied on City GIS mapping with the assumption that City critical areas maps are accurately depicted in the City GIS. 5.0 STEEP SLOPE HAZARDS AND MITIGATIONS The site contains areas mapped by the City of Renton GIS to be Sensitive Slopes, with inclinations of up to 40 percent. Sensitive slopes trigger the requirement for a Special Study in accordance with RMC Section 4-3-050 J2. The site is not mapped to contain Protected Slopes. The RMC imposes development limitations on Protected Slopes, but not Sensitive Slopes. From a practical standpoint, in our experience slopes with inclinations and heights similar to those that currently exist at the site, and which are underlain by dense lodgement till sediments, are not typically considered to be at substantial risk of slope failures. 6.0 SEISMIC HAZARDS AND MITIGATIONS Earthquakes occur regularly in the Puget Lowland. Most of these events are small and are not felt by people. However, large earthquakes do occur, as evidenced by the 2001, 6.8-magnitude event; the 1965, 6.5-magnitude event; and the 1949, 7.2-magnitude event. The 1949 earthquake appears to have been the largest in this region during recorded history and was centered in the Olympia area. Evaluation of earthquake return rates indicates that an earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period. Generally, there are four types of potential geologic hazards associated with large seismic events: 1) surficial ground rupture, 2) seismically induced landslides, 3) liquefaction, and 4) ground motion. The potential for each of these hazards to adversely impact the proposed project is discussed below. Review of City GIS maps indicates that the site is not underlain by areas considered by the City of Renton to be Seismic Hazard Areas. September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pc/ld - KE120359A4 - Projects120120359IKEIWP Page 5 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations 6.1 Surficial Ground Rupture The nearest known fault to the project site is the Seattle Fault Zone. Recent studies of the Seattle Fault Zone indicate that it is an active fault zone capable of generating surface ruptures. The Seattle Fault Zone is not well understood, and is an area of active research. According to the U.S. Geological Survey (USGS) studies, the recurrence interval of movements along the Seattle Fault Zone is unknown, but is speculated to be on the order of 1,100 years. The site is south of the currently recognized limits of the Seattle Fault Zone. 6.2 Seismically Induced Landslides The site is underlain at shallow depths by lodgement till, which typically performs well from a slope stability standpoint when exposed on slopes with inclinations such as those that currently exist on-site. In its current condition the site does not appear to be at substantial risk of seismically induced landslides. 6.3 Liquefaction Liquefaction is a temporary loss in soil shear strength that can occur when loose granular soils below the ground water table are exposed to cyclic accelerations, such as those that occur during earthquakes. The observed site soils are very dense and silty and are not considered to be susceptible to liquefaction. No quantitative liquefaction analysis was completed for this study, and none is warranted for the project as currently proposed, in our opinion. 6.4 Ground Motion Structural design of buildings should follow the current applicable building code. The applicable code at the time this report was written is the 2009 International Building Code (IBC). The lodgement till soils observed in our explorations are consistent with 2009 IBC Site Class "C", as defined in IBC Table 1613.5.2. 7.0 EROSION HAZARDS AND MITIGATIONS The site does not contain areas identified as High Erosion Hazard Areas in the City of Renton GIS. The site may contain areas considered by the City to be Low Erosion Hazard Areas, though Low Erosion Hazard Areas are not mapped in the City of Renton GIS and RMC does not impose substantial development limitations on sites with Low Erosion Hazards. We anticipate that any future development project on site will comply with the Washington State Department of Ecology (Ecology) requirements for Construction Storm Water General Permits. We anticipate that permit conditions will require the use of Temporary Erosion and September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pc/ld - KE120359A4 - Projects120120359IKEIWP Page 6 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations Sedimentation Controls (TESCs) in accordance with local standards of practice, completion of weekly TESC checklists, and monitoring of construction storm water turbidity and pH. 8.0 COAL MINE HAZARDS An area west of the subject property was developed with underground coal mines in the past. Depending on the proximity, depth, and nature of the underground workings, sites underlain by old coal mines may be at risk of ground subsidence or other adverse effects. Typically sites that are known to be at risk of damage from coal mine hazards are subjected to a detailed assessment that includes research of historical coal mine maps, and often deep subsurface explorations. The purpose of these studies is to determine if coal mine hazards are actually present, to characterize any hazards, and to formulate coal mine hazard mitigation measures. These studies require a substantial commitment of time and effort, and are warranted in cases where existing data suggests that coal mine hazards may be present. The site is located approximately 250 feet east of the limit of an area of Moderate Coal Mine Hazards identified on the City of Renton GIS. Review of King County Imap resources indicates that the County considers the limits of the Coal Mine Hazard Area to be farther from the site boundary than does the City of Renton. The City of Renton does not require a Special Study for areas that lie more than 50 feet outside the limits of mapped Coal Mine Hazard Areas. Associated Earth Sciences, Inc. (AESI) did not complete a coal mine hazard assessment as part of this study. September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pcIld - KE120359A4 - Projects120120359IKEIWP Page 7 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations III. PRELIMINARY DESIGN RECOMMENDATIONS Our exploration indicates that, from a geotechnical engineering standpoint, the site is suitable for support of conventional paving, lightly-loaded structures, and typical buried utilities. Support of moderate to high foundation loads would likely be technically feasible but is not expected to be needed for a future project at this site. Any specific development plan for the site should be supported by a geotechnical engineering report written specifically for the proposed project. This report is intended to provide feasibility-level preliminary geotechnical information. 9.0 GEOTECHNICAL FEASIBILITY AND PRELIMINARY RECOMMENDATIONS 9.1 Site Preparation Site preparation of building and paving areas should include removal of all grass, trees, brush, debris, and any other deleterious materials. Any existing fill should be removed. Existing topsoil should be stripped from structural areas. The actual observed in-place depth of topsoil and grass at the exploration locations is presented on the exploration logs in the Appendix. After stripping, remaining roots and stumps should be removed from structural areas. All soils disturbed by stripping and grubbing operations should be recompacted as described below for structural fill. Once excavation to subgrade elevation is complete, the resulting surface should be proof-rolled with a loaded dump truck or other suitable equipment. Any soft, loose, yielding areas or areas exposing existing fill should be excavated to expose suitable bearing soils. The subgrade should then be compacted to at least 95 percent of the modified Proctor maximum dry density, as determined by the American Society for Testing and Materials (ASTM):D 1557 test procedure. Structural fill can then be placed to achieve desired grades, if needed. 9.2 Temporary Cut Slopes In our opinion, stable construction slopes should be the responsibility of the contractor and should be determined during construction. For estimating purposes, however, temporary, unsupported cut slopes can be planned at 1.5H:1V (Horizontal:Vertical) in unsaturated weathered lodgement till, and at 1H:1V in dense, unweathered till. These slope angles are for areas where ground water seepage is not present at the faces of the slopes, which may require temporary dewatering in the form of pumped sumps or other measures. If ground or surface water is present when the temporary excavation slopes are exposed, flatter slope angles may be required. As is typical with earthwork operations, some September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BIVG/pc/Id - KE120359A4 - Projects120120359IKEIWP Page 8 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations sloughing and raveling may occur, and cut slopes may have to be adjusted in the field. In addition, WISHA/OSHA regulations should be followed at all times. 9.3 Site Disturbance The on-site soils contain fine-grained material, which makes them moisture-sensitive and subject to disturbance when wet. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. 9.4 Winter Construction The lodgement till sediments contain substantial silt and are considered highly moisture-sensitive. We anticipate that most of the lodgement till sediments are above optimum moisture content for compaction purposes. It appears likely that soils excavated on-site will require drying during favorable dry weather conditions to allow their reuse in structural fill applications. Care should be taken to seal all earthwork areas during mass grading at the end of each workday by grading all surfaces to drain and sealing them with a smooth-drum roller. Stockpiled soils that will be reused in structural fill applications should be covered whenever rain is possible. If winter construction is expected, crushed rock fill could be used to provide construction staging areas. The stripped subgrade should be observed by the geotechnical engineer, and should then be covered with a geotextile fabric, such as Mirafi 500X, or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer at least 10 inches thick in areas where construction equipment will be used. 9.5 Structural Fill We anticipate that cuts and fills of up to about 10 feet could be required to establish subgrades for roads and buildings. Structural fill material selection and compaction standards should be determined based on the specific site development plan that is proposed. The native sediments on-site are expected to provide adequate support for structural fill if properly prepared. Excavated site soils could be used in structural fill applications but would require that earthwork be completed during favorable dry site and weather conditions when excavated materials can be aerated to reduce moisture content prior to compaction. The reuse of excavated on-site soil in structural fill applications will also require careful planning on the part of the contractor to accommodate the extreme moisture sensitivity of the site soils and to limit site disturbance. September 28, 2012 ASSOCIATED EARTH SCIENCES, INC. BWG/pc/ld - KE120359A4 - Projects120120359IKEIWP Page 9 Subsurface Exploration, Geologic Hazard, Tiffany Park Site and Limited Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations 9.6 Foundations We anticipate that natural sediments observed at shallow depths in our exploration pits will provide adequate support for lightly-loaded foundations and floor slabs with proper preparation. Typical foundation soil bearing pressures of up to 3,000 pounds per square foot (psf) are feasible. Higher foundation soil bearing pressures are technically feasible with the soils we observed on-site but are not expected to be needed. 9.7 Pavement Recommendations We anticipate that properly prepared native site soils will be suitable to support pavement sections that are typical for the intended use. We recommend that any public streets be designed to City of Renton standards. Private driveways and parking areas should be designed to support actual expected traffic loads when a project plan has been formulated and pavement usage can be estimated. 10.0 PROJECT DESIGN AND CONSTRUCTION MONITORING This report is based on previously referenced topographic survey information and on our observations of subsurface conditions. We recommend that this preliminary geotechnical feasibility report be reviewed and modified as needed to support any specific future project. We have enjoyed working with you on this study. If you should have any questions or require further assistance, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Bruce W. Guenzler, L.E.G. Kurt D. Merriman, P.E. Project Geologist Senior Principal Engineer Attachments: Figure 1: Vicinity Map Figure 2: Site and Exploration Plan Appendix: Exploration Logs September 28, 2012 BWG/pcIld - KE120359A4 - Projects1201203591KEIWP ASSOCIATED EARTH SCIENCES, INC. Page 10 NOTE: BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION. REFERENCE: USGS TOPO! 2000 Associated Earth Sciences, Inc. VICINITY MAP TIFFANY PARK SITE RENTON, WASHINGTON FIGURE 1 DATE 9/12 PROJ. NO. KE120359A iii • ' 12 0 3 5 9 Re n to n S D - Fa ir wo o d S it e 11 2 0 3 5 9 Vi c in it y . c dr REFERENCE: AHBL 0 75 150 FEET 12 03 5 9 R e n to n SD \ Fa ir w o o d Si t e \ 12 0 3 59 Si t e a n d E x p lr . c dr Associated Earth Sciences, Inc. SITE AND EXPLORATION PLAN TIFFANY PARK SITE RENTON, WASHINGTON FIGURE 2 DATE 9/12 PROJ. NO. KE120359A / EP-3 APPROXIMATE LOCATION OF EXPLORATION PIT TYP N • EP-2 • EP-1 EP-11 NI EP-12 EP-5 gl 1 1 1 1 1 1 1 1 1 1 LI EP-9 EP-6 L .%\ • / 1 •,? ,c‘9 ar- • wi4,24 I 4'2 ' 4 EP-8 EP-7 II EP-10 1 1 1 I 1 y 00 . ---- --------- EP APPENDIX FIGURE Al EXPLORATION LOG KEY Co a r s e - Gr a in e d S o i ls - M o r e t ha n 50 % (1) Re ta in e d o n N o . 2 0 0 S i e v e Gr a ve ls - M o re t ha n 5 0 % (1) o f C o a r s e F r a c t io n l Re ta in e d o n No . _ 4 S i e ve 5% Fi n e s (5 / , c, AA oV oV ,c, 8.0 8.0 . J C:3 C GW Well-graded gravel and gravel with sand, little to no fines Terms Describing Relative Density and Consistency Density SPT(2)blows/foot Very Loose 0 to 4 Coarse- Loose 4 to 10 Grained Soils Medium Dense 10 to 30 Test Symbols Dense 30 to 50 Very Dense >50 G = Grain Size M = Moisture Content Consistency SPT(2)blows/foot A = Atterberg Limits 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 GP Poorly-graded gravel and gravel with sand, little to no fines s cu if g_ al . 0 1111. ° 11...11.. . a VI c ° . • GM Silty gravel and silty gravel with sand Very Soft 0 to 2 C = Chemical Fine- Soft 2 to 4 DD = Dry Density Grained Soils Medium Stiff 4 to 8 K = Permeability Stiff 8 to 15 Very Stiff 15 to 30 Hard >30 i.-- ,4 -.-1..*-.1 ir.,,,, 1#10 Ir..71, G C Clayey gravel and clayey gravel with sand Component Definitions Descriptive Term Size Range and Sieve Number Sa n ds - 5 0 % (1) or M o r e o f C o a r s e Fr a c ti o n Pa s s e s N o . 4 S ie v e 5% F i n e s (5) •:::•:•:•:.: X -: .:.:.:.: :. • SW Well-graded sand and sand with gravel, little to no fines Boulders Larger than 12" Cobbles 3' to 12" Gravel 3" to No. 4 (4.75 mm) Coarse Gravel 3" to 3/4" Fine Gravel 3/4" to No. 4 (4,75 mm) Sand No. 4 (4.75 mm) to No. 200 (0.075 mm) Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm) Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm) Fine Sand No. 40 (0A25 mm) to No. 200 (0.075 mm) Silt and Clay Smaller than No. 200 (0.075 mm) • SP Poorly-graded sand and sand with gravel, little to no fines 15 % Fi n e s (5) SRil Silty sand and silty sand with gravel sc Clayey sand and clayey sand with gravel (3) Estimated Percentage Moisture Content Percentage by Dry - Absence of moisture, Component Weight dusty, dry to the touch Fi n e - Gr a in e d S o il s - 5 0 % (1) or M o r e P a s se s No . 2 0 0 Si e v e Si lt s a n d C la y s L iq u id L i m it L e s s t h a n 5 0 ML Silt, sandy silt, gravelly silt, silt with sand or gravel Trace <5 Slightly Moist - Perceptible Few 5 to 10 moisture Little 15 to 25 Moist - Damp but no visible With - Non-primary coarse water constituents: > 15% Very Moist - Water visible but - Fines content between not free draining 5% and 15% Wet - Visible free water, usually from below water table A. CI. Clay of low to medium plasticity; silty, sandy, or gravelly clay, lean clay , :: — OL Organic clay or silt of low plasticity Symbols Blows/6" or Sampler portion of 6" Type 2. 0 " OD / Sampler Type 4 4 Cement grout .t.1 surface seal S il t s a n d C la y s Li q u id L i m it 5 0 o r M o r e MH Elastic silt, clayey silt, silt with micaceous or diatomaceous fine sand or silt Split-Spoon r ;: Description 4) Bentonite seal Sampler (SP1) Bulk sample Grab Sample 4 III 3.0" OD Split-Spoon Sampler - I 3.25" OD Split-Spoon Ring Sampler (4) vi. 1 3.0" OD Thin-Wall Tube Sampler • _ (including Shelby tube) it ". _ Le : 111•• 2.-' Filter pack with : blank casing . section • Screened casing or Hydrotip •.• with filter pack End cap r CH Clay of high plasticity, sandy or gravelly clay, fat clay with sand or gravel 1010 .//i '//0/, ''..,/* .,-..., OH Organic clay or silt of medium to high plasticity o Portion not recovered (1) Percentage by dry weight M Depth of ground water (2) (SPT) Standard Penetration Test (ASTM D-1586) Y. ATD = At time of drilling a Static water level (date) (3) In General Accordance with Standard Practice for Description (5) Combined USCS symbols used for and Identification of Soils (ASTM D-2488) fines between 5% and 15% 0 >-. - .e .0 cn a 5 O PT Peat, muck and other highly organic soils -1--H÷ I' .i,,,_,,......,1,.....,,..... ''''`t`j.- ti Classifications of soils in his report are based on visual field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and plasticity estimates and should not be construed to imply field or laboratory testing unless presented herein. Visual-manual and/or laboratory classification methods of ASTM D-2487 and D-2488 were used as an identification guide for the Unified Soil Classification System, Associated Earth Sciences, Inc. lo c ks 1 lo g _ ke y . dw g LA YO U T : L a y ou t 2 LOG OF EXPLORATION PIT NO. EP-1 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil 1 — Weathered Vashon Lodgement Till 2 — Medium dense, moist, mottled gray and brown, fine to coarse SAND, with silt, little fine to coarse gravel; no stratification or structure (SM). 3 — 4 — 5 — Vashon Lodgement Till / Vashon Advance Outwash Transitional Sediments 6 — Dense, moist, brown, fine to coarse SAND, with fine to coarse gravel, few silt; no stratification (SW). 7 — 8 — Very dense, moist, mottled gray, fine to coarse SAND, with silt, little fine to coarse gravel; no 9 — stratification or structure (SM). 10 — 11 — Bottom of exploration pit at depth 10.5 feet No seepage. No caving. 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — K C — P3 1 2 0 3 5 9 . GP J S e p te m be r 1 8 , 2 0 12 Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Project No. KE120359A 9/6/12 Logged by: BWG Approved by: LOG OF EXPLORATION PIT NO. EP-2 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 Topsoil 2 — 3 — 4 Weathered Vashon Lodgement Till Medium dense, moist, light brown, fine SAND, with silt, few fine gravel; no stratification or structure (SM). 6 — 7 — 8 — 9 — 10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Vashon Lodgement Till / Vashon Advance Outwash Transition Sediments Dense grading to very dense, very moist, mottled gray grading to gray, fine to coarse SAND, with silt, little fine gravel (SM); pockets of gray, fine to medium SAND, few silt (SP). Bottom of exploration pit at depth 10.5 feet No seepage. No caving. K CT P 3 1 2 0 3 5 9. G PJ S e p te m be r 1 8 , 2 01 2 Logged by: BWG Approved by: Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Project No. KE120359A 9/6/12 LOG OF EXPLORATION PIT NO. EP-3 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — 4 5 — 6 — 7 — 8 — 9 — 10 Topsoil Weathered Vashon Lodgement Till Medium dense, moist, light brown, fine SAND, with silt, few fine gravel; no stratification or structure (SM). Vashon Lodgement Till Dense grading to very dense, very moist, gray, fine to coarse SAND, with silt, few fine gravel; no stratification or structure (SM). 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Bottom of exploration pit at depth 10 feet No seepage. No caving. K CT P 3 1 2 0 3 5 9 . GP J Se p te m be r 18 , 2 Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Logged by: BWG Approved by: Project No. KE120359A 9/6/12 LOG OF EXPLORATION PIT NO. EP-4 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — 4 — 5 — 6 — 7 — 8 -- 9 — 10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Topsoil Weathered Vashon Lodgement Till Medium dense, moist, reddish brown, fine to medium SAND, with silt, few fine gravel; no stratification or structure (SM). Vashon Lodgement Till Dense grading to very dense, moist, gray, fine to coarse SAND, with silt, few fine gravel; no stratification or structure (SM). Bottom of exploration pit at depth 10.5 feet No seepage. No caving. KC T P 3 1 2 03 5 9 . GP J Se p te m be r 1 8 , 2 0 12 Logged by: BWG Approved by: Tiffany Park Site Renton, WA Associated Earth Sciences, Inc Project No. KE120359A 9/6/12 LOG OF EXPLORATION PIT NO. EP-5 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — Topsoil Weathered Vashon Lodgement Till Medium dense, moist, mottled brown, fine to medium SAND, with silt, few fine gravel; no stratification or structure (SM). 4 5 — 6 — 7 — 8 — 9 — 10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Vashon Lodgement Till Dense grading to very dense, very moist, mottled gray, fine to coarse SAND, with silt (SM). Bottom of exploration pit at depth 10.5 feet No seepage. No caving. K CT P 3 1 2 0 3 5 9. G PJ Se p te m be r 1 8 , 2 0 12 Tiffany Park Site Renton, WA Associated Earth Sciences, Inc Project No. KE120359A 9/6/12 Logged by: BWG Approved by: LOG OF EXPLORATION PIT NO. EP-6 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — 4 — 5 — 6 — 7 — 8 — 9 — Topsoil Weathered Vashon Lodgement Till Medium dense, moist, mottled brown, fine to coarse SAND, with silt, little fine to coarse gravel; no stratification or structure (SM). Vashon Lodgement Till Dense grading to very dense, very moist to wet, mottled gray grading to gray, fine to coarse SAND, with silt, little fine to coarse gravel; no stratification or structure (SM). 10 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Bottom of exploration pit at depth 10 feet Weak seepage zones below 8 feet. No caving. KC T P3 12 0 3 5 9 . GP J S e p te m be r 18 , 2 0 1 2 Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Project No. KE120359A 9/6/12 Logged by: BWG Approved by: LOG OF EXPLORATION PIT NO. EP-7 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil 1 — Weathered Vashon Lodgement Till 2 — Medium dense, moist, light brown, fine SAND, with silt, few fine gravel; no stratification or structure (SM). 3 — 4 — Vashon Lodgement Till Dense grading to very dense, very moist, mottled gray grading to gray, fine to coarse SAND, with silt, little fine gravel, trace coarse gravel and cobbles, one boulder; no stratification or structure 6 — (SM). 7 — 8 — 9 — 10 Bottom of exploration pit at depth 10 feet 11 — No seepage. No caving. 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — K C T P 3 1 2 0 35 9. GP J Se p te m be r 1 8 , 2 0 1 2 Tiffany Park Site Renton, WA Associated Earth Sciences, Inc Project No. KE120359A 9/6/12 Logged by: BWG Approved by: LOG OF EXPLORATION PIT NO. EP-8 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — Topsoil Weathered Vashon Lodgement Till Medium dense, very moist, reddish brown, fine to medium SAND, with silt, few fine to coarse gravel; no stratification or structure (SM). 4 5 — 6 — 7 — 8 — 9 — Vashon Lodgement Till Dense grading to very dense, very moist, mottled gray, fine to coarse SAND, with silt, little fine to coarse gravel, trace cobbles; no stratification or structure (SM). 10 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Bottom of exploration pit at depth 10 feet No seepage. No caving. KC TP 3 1 2 0 3 5 9 . GP J S e p te m be r 1 8 , 20 1 2 Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Project No. KE120359A 9/6/12 Logged by: BWG Approved by: LOG OF EXPLORATION PIT NO. EP-9 P3 1 2 0 3 5 9. G PJ Se p te m be r 1 8 , 2 0 1 2 Logged by: BWG Approved by: Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 _ 4 Topsoil Weathered Vashon Lodgement Till Medium dense, moist, mottled brown, fine to medium SAND, with silt; no stratification or structure (SM). 5 — 6 — 7 — 8 — Vashon Lodgement Till Dense grading to very dense, very moist, mottled gray, fine to coarse SAND, with silt, little fine to coarse gravel, trace cobbles and boulders; no stratification or structure (SM). 9 10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Bottom of exploration pit at depth 9 feet No seepage. No caving. Project No. KE120359A 9/6/12 LOG OF EXPLORATION PIT NO. EP-10 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — 4 Topsoil Weathered Vashon Lodgement Till Medium dense, moist, light brown, fine SAND, with silt, trace fine gravel; no stratification or structure (SM). 5 — 6 — 7 — Vashon Lodgement Till Dense grading to very dense, moist, mottled gray, fine to coarse SAND, with silt, few fine to coarse gravel; no stratification or structure (SM). 8 9 — 10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Bottom of exploration pit at depth 8 feet No seepage. No caving. KC T P 3 1 2 0 3 5 9. GP J Se p te m be r 18 , Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Logged by: BWG Approved by: Project No. KE120359A 9/6/12 LOG OF EXPLORATION PIT NO. EP-11 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — 4 Topsoil Weathered Vashon Lodgement Till Medium dense, moist, light brown, fine SAND, with silt, trace fine gravel; no stratification or structure (SM). 5 — 6 — 7 — 8 — 9 — 10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Vashon Lodgement Till Dense grading to very dense, very moist, mottled gray, fine to medium SAND, with silt, few fine to coarse gravel, trace cobbles; no stratification or structure (SM). Bottom of exploration pit at depth 8.5 feet No seepage. No caving. KC T P 3 1 2 0 3 5 9 . GP J S e p te m be r 18 , 2 0 1 2 Logged by: BWG Approved by: Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. I r Project No. KE120359A 9/6/12 LOG OF EXPLORATION PIT NO. EP-12 De p t h ( ft ) This log is part of the report prepared by Associated Earth Sciences, Inc. (A ESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION 1 — 2 — 3 — 4 — 5 — 6 — 7 — 8 — 9 — 10 Topsoil Weathered Vashon Lodgement Till Medium dense, moist, light brown, fine SAND, with silt, trace fine gravel; no stratification or structure (SM). Vashon Lodgement Till Dense grading to very dense, moist, mottled brown and gray grading to gray, fine to coarse SAND, with silt, few fine gravel; no stratification or structure (SM). 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — Bottom of exploration pit at depth 10 feet No seepage. No caving. KC TP 3 12 0 3 5 9 . G PJ Se p te m be r 1 8 , 20 1 2 Logged by: BWG Approved by: Tiffany Park Site Renton, WA Associated Earth Sciences, Inc. Project No. KE120359A 9/6/12