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HomeMy WebLinkAboutRS_Geotechnical Report_Associated Earth Sciences_190419_V1 Kirkland Office | 911 Fifth Avenue | Kirkland, WA 98033 P | 425.827.7701 Mount Vernon Office | 508 S. Second Street, Suite 101 | Mount Vernon, WA 98273 P | 425.827.7701 Tacoma Office | 1552 Commerce Street, Suite 102 | Tacoma, WA 98402 P | 253.722.2992 www.aesgeo.com April 19, 2019 Project No. 190165E001 Dalpay Properties c/o Goldsmith Engineering 1215 112th Avenue SE Bellevue, Washington 98004 Attention: Mr. Tom Dalpay Subject: Limited Subsurface Exploration and Geotechnical Engineering Report Dalpay Short Plat State Route 900 and 148th Avenue SE Renton, Washington Dear Mr. Dalpay: As requested, this letter-report presents the results of our subsurface exploration and geotechnical engineering services for the above-referenced project. Our understanding of the project is based on our discussions with you and review of a preliminary lot layout plan for the property, dated April 10, 2019. Written authorization to proceed with this study was granted by Mr. Tom Dalpay. Our study was accomplished in general accordance with our scope of work as presented in a signed contract dated, April 11, 2019. This letter-report has been modified and updated from a previous report prepared by Associated Earth Sciences, Inc (AESI) for a previous client interested in developing the property in October 2016. The previous client has granted permission to use the findings of the prior report. This letter-report has been prepared for the exclusive use of Dalpay Properties and their agents for specific application to this project. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering practices in effect, in this area at the time our letter-report was prepared. Our observations, findings, and opinions are a means to identify and reduce the inherent risks to the owner. No other warranty, express or implied, is made. Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 2 SITE AND PROJECT DESCRIPTION The project site is located at the northwest corner of the intersection of State Route 900 and 148th Avenue SE (Nile Avenue NE) in Renton, Washington and consists of King County Tax Parcel Number 0323059120. The parcel is trapezoidal shaped in plan view and is approximately 2.47 acres in area. The site location is shown on the “Vicinity Map,” Figure 1. The parcel is currently undeveloped and is vegetated with tall grasses, dense blackberry brambles, and scattered stands of young deciduous trees along portions of the perimeter of the parcel. Site topography generally slopes downward toward the northwest and west. The west side of the site gradually slopes downward toward Greenes Creek, which flows to the north and is located just west of the western property line. AESI performed a site reconnaissance of the property on April 16, 2019, as part of preparation of this updated report. The observed site conditions were similar to those observed during our prior study. No discernable changes to the site conditions were observed, and we observed no surface water on the site and in the Greenes Creek drainage to the west of the property. Based on the above-referenced plan, we understand that the project will consist of subdividing the parcel into five lots and a stormwater tract. Single-family residences are proposed on each of the five lots. The stormwater tract is situated at the topographically lowest northwestern corner of the parcel. We understand the project will also consist of construction of a southward extension of Mount Baker Place NE into the property from the north. At the time this letter-report was prepared, the project was in the conceptual planning stage and no further project layout or plans had been formulated. SUBSURFACE EXPLORATION AND CONDITIONS Our subsurface exploration completed for this project included the excavation of six exploration pits dug on October 12, 2016. The conclusions and recommendations presented in this letter-report are based on the explorations completed for this study. The locations and depths of the explorations were completed within site and budget constraints. The approximate locations of explorations completed for this study are presented on the “Site and Exploration Plan,” Figure 2. Copies of the subsurface exploration logs are also attached with this letter-report in the Appendix. The exploration pits were excavated using a tracked mini excavator provided and operated by Northwest Excavating & Trucking (NW), under subcontract to AESI. The pits permitted direct, visual observation of subsurface conditions. Materials encountered in the exploration pits were studied and classified in the field by an experienced geotechnical engineer from our firm. All exploration pits were backfilled after examination and logging. Selected samples were then transported to our laboratory for further visual classification. Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 3 Our explorations generally encountered shallow, native lodgement till soils. The encountered lodgement till was weathered near the surface consisting of medium dense, moist, tan, silty sand with gravel and was unsorted. At depths of 2 to 3 feet below the surface the lodgement till graded to unweathered till that consisted of dense, gray, silty fine sand with gravel and was unsorted. Lodgement till was deposited at the base of an active continental glacier during the Vashon Stade of the Fraser Glaciation approximately 12,500 to 15,000 years ago. The till was compacted by the weight of about 3,000 feet of overlying ice. Lodgement till typically has high-strength and low-compressibility attributes that are favorable for structural support with proper preparation. Lodgement till is typically silty, moisture-sensitive, and easily disturbed under wet site or weather conditions. Excavated lodgement till is suitable for reuse in structural fill applications under dry site and weather conditions when it can be moisture-conditioned to allow compaction to a firm and unyielding condition at the specified level for the intended purpose. Lodgement till is considered suitable for foundation support but is not considered a suitable infiltration receptor. The geologic units identified on the subject property closely match those units identified within the site area on the Geologic Map of King County, compiled by Derek B. Booth, Kathy A. Troost, and Aaron P. Wisher, dated March 2007. Hydrology Groundwater was not observed in any of our explorations. We anticipate that shallow groundwater will be limited to interflow. Interflow commonly occurs in areas underlain by glacially consolidated sediments and originates as surface water that percolates down through the near-surface, relatively permeable surface soils, such as weathered lodgement till, and becomes trapped or “perched” atop the underlying, relatively impermeable, glacial sediments. Interflow is often a seasonal phenomenon. It should be noted that the presence and depth of seepage at the site may vary in response to such factors as changes in season, precipitation, and site use. Infiltration Feasibility The site is underlain at shallow depths by medium dense to very dense lodgement till. Lodgement till generally consisted of silty fine sand with gravel and has been consolidated by the weight of an overriding ice sheet during the most recent ice age. As a result, the lodgement till has a low permeability due to its relative high density and high silt content and is not a suitable receptor for infiltration. In addition, the till layer commonly creates a perched groundwater layer described in the previous section that will not allow adequate separation from high winter groundwater, for a proposed infiltration facility, if present. With deeper explorations infiltration strategies into the geologic unit underlying the lodgement till might be feasible if present. However, this would require completion of deeper subsurface explorations which was beyond the scope of this study and would require drilling to attain the proper depths and the installation of a groundwater Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 4 monitoring well. Information critical to deep infiltration includes thickness of overlying lodgement till, depth to the receptor horizon (in this case, likely Vashon advance outwash sand), permeability of the receptor horizon, and depth to the regional groundwater table. DESIGN RECOMMENDATIONS Introduction Our explorations indicate that, from a geotechnical standpoint, the proposed project is feasible provided the recommendations contained herein are properly followed. The bearing stratum is generally shallow and conventional shallow foundations should perform well with proper subgrade preparation. We recommend that building foundations are founded on the dense native, glacial till soils or structural fill placed on top of the native glacial till. Site Preparation Site preparation of the construction area should include removal of all grass, brush, debris, and any other deleterious materials. Erosion and surface water control should be established around the clearing limits to satisfy local requirements. We recommend existing fill, if encountered, be removed from below areas of shallow foundations. When structural fill is required for restoration of the planned foundation grade, our recommendations detailed in the “Structural Fill” section should be followed. Removal of unsuitable soil should extend laterally beyond the building footprint by a distance equal to the depth of overexcavation. For example, when existing fill is removed to a depth of 2 feet below a planned footing area, the excavation should also extend laterally 2 feet beyond the building footprint in that area. Where existing fill is removed and replaced with structural fill, conventional shallow foundations may be used for structure support. The required depth of removal should be determined in the field based on actual conditions encountered during excavation. Below planned on-site paving or under building slabs-on-grade, the stripped subgrade should be proof-rolled with heavy, rubber-tired construction equipment, such as a fully loaded tandem-axle dump truck. Proof-rolling should be performed prior to structural fill placement. The proof-roll should be monitored by the geotechnical engineer so that any soft or yielding subgrade soils can be identified. Any soft or loose, yielding soils should be removed to a stable subgrade. Proof-rolling should only be attempted if soil moisture contents are at or near optimum moisture content. Proof-rolling of wet subgrades could result in further degradation. Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 5 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) or flatter in the existing fill and underlying weathered glacial deposits, provided they are not saturated. Temporary slopes in unsaturated, unweathered lodgement till may be planned at 1H:1V. These slope angles are for areas where groundwater seepage is not encountered, and assume that surface water is not allowed to flow across the temporary slope faces. If ground or surface water is present when the temporary excavation slopes are exposed, flatter slope angles will be required. As is typical with earthwork operations, some 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. Site Disturbance The on-site soils contain a high percentage of fine-grained material, which makes them easy to disturb during wet weather. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened during wet weather conditions. Structural Fill All references to structural fill in this letter-report refer to subgrade preparation, fill type and placement, and compaction of materials, as discussed in this section. If a percentage of compaction is specified under another section of this letter-report, the value given in that section should be used. After stripping, planned excavation, and any required overexcavation have been performed to the satisfaction of the geotechnical engineer, the upper 12 inches of exposed ground in areas to receive fill should be recompacted to a firm and unyielding condition. If the subgrade contains silty soils and too much moisture, adequate recompaction may be difficult or impossible to obtain and should probably not be attempted. In lieu of recompaction, the area to receive fill should be blanketed with washed rock or quarry spalls to act as a capillary break between the new fill and the wet subgrade. Where the exposed ground remains soft and further overexcavation is impractical, placement of an engineering stabilization fabric may be necessary to prevent contamination of the free-draining layer by silt migration from below. After recompaction of the exposed ground is approved, or a free-draining rock course is laid, structural fill may be placed to attain desired grades. Structural fill is defined as non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts, with each lift being Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 6 compacted to 95 percent of the modified Proctor maximum density using American Society for Testing and Materials (ASTM) D-1557 as the standard. Use of soils from the site in structural fill applications is acceptable if the material meets the project specifications for the intended use, and if specifically allowed by project specifications. In the case of roadway and utility trench filling, structural fill should be placed and compacted in accordance with current City of Renton codes and standards. The top of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond the locations of the roadway edges before sloping down at an angle of 2H:1V. Structural fills with sloping faces that cannot be compacted directly by a vibratory roller should be compacted by overbuilding, then cutting back to a compacted slope core. The contractor should note that any proposed fill soils must be evaluated by AESI prior to their use in fills. This would require that we have a sample of the material 72 hours in advance to perform a Proctor test and determine its field compaction standard. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Use of moisture-sensitive soil in structural fills should be limited to favorable dry weather conditions, and is only permitted if specifically allowed by project plans and specifications. The native soils present onsite contained significant amounts of silt and are considered highly moisture-sensitive. If fill is placed during wet weather or if proper compaction cannot be obtained, a select import material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction with at least 25 percent retained on the No. 4 sieve. A representative from our firm should inspect the stripped subgrade and be present during placement of structural fill to observe the work and perform a representative number of in-place density tests. In this way, the adequacy of the earthwork may be evaluated as filling progresses, and any problem areas may be corrected at that time. It is important to understand that taking random compaction tests on a part-time basis will not assure uniformity or acceptable performance of a fill. As such, we are available to aid the owner in developing a suitable monitoring and testing program. Ground Motion Structural design of the project should be in accordance with the 2015 International Building Code (IBC) using Site Class D. Foundations Spread footings that are supported on dense native lodgement till sediments or a combination of structural fill and dense native lodgement till sediments may be designed with an allowable Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 7 foundation soil bearing pressure of 3,000 pounds per square foot (psf), including both dead and live loads. An increase of one-third may be used for short-term wind or seismic loading. Perimeter footings should be buried at least 18 inches into the surrounding soil for frost protection. However, all footings must penetrate to the prescribed bearing stratum, and no footing should be founded in or above organic or loose soils. It should be noted that the area bound by lines extending downward at 1H:1V from any footing must not intersect another footing or intersect a filled area that has not been compacted to at least 95 percent of ASTM D-1557. In addition, a 1.5H:1V line extending down from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in the bearing soils. Anticipated settlement of footings founded as described above should be on the order of ½ inch or less. However, disturbed soil not removed from footing excavations prior to footing placement could result in increased settlements. All footing areas should be inspected by AESI prior to placing concrete to verify that the design bearing capacity of the soils has been attained and that construction conforms to the recommendations contained in this letter-report. Such inspections may be required by the governing municipality. Perimeter footing drains should be provided, as discussed under the “Drainage Considerations” section of this letter-report. Lateral loads can be resisted by friction between the foundation and the natural glacial soils or supporting structural fill soils, and by passive earth pressure acting on the buried portions of the foundations. The foundations must be backfilled with structural fill and compacted to at least 95 percent of the maximum dry density to achieve the passive resistance provided below. We recommend the following allowable design parameters: • Passive equivalent fluid = 350 pounds per cubic foot (pcf) • Coefficient of friction = 0.35 Drainage Considerations Foundations should be provided with foundation drains. Drains should consist of rigid, perforated, polyvinyl chloride (PVC) pipe surrounded by washed pea gravel. The drains should be constructed with sufficient gradient to allow gravity discharge away from the proposed building. Roof and surface runoff should not discharge into the footing drain system, but should be handled by a separate, rigid, tightline drain. In planning, exterior grades adjacent to walls should be sloped downward away from the proposed building to achieve surface drainage. Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 8 Lateral Wall Pressures All backfill behind foundation walls or around foundation units should be placed as per our recommendations for structural fill and as described in this section of the letter-report. Horizontally backfilled walls, which are drained and free to yield laterally at least 0.1 percent of their height, may be designed to resist active lateral earth pressure represented by an equivalent fluid equal to 35 pcf. Fully restrained, drained, horizontally backfilled, rigid walls that cannot yield should be designed for an at-rest equivalent fluid of 50 pcf. If parking areas are adjacent to walls, a surcharge equivalent to 2 feet of soil should be added to the wall height in determining lateral design forces. Walls with sloping backfill are not expected; however, if walls with sloping backfill are planned, we should be contacted to offer situation-specific surcharge recommendations. As required by the 2015 IBC, retaining wall design should include a seismic surcharge pressure in addition to the equivalent fluid pressures presented above. Considering the site soils and the recommended wall backfill materials, we recommend a seismic surcharge pressure of 8H and 11H psf, where H is the wall height in feet, for the “active” and “at-rest” loading conditions, respectively. The seismic surcharge should be modeled as a rectangular distribution with the resultant applied at the midpoint of the walls. The lateral pressures presented above are based on the conditions of a uniform backfill consisting of excavated on-site soils, or imported structural fill compacted to 90 percent of ASTM D-1557. A higher degree of compaction is not recommended, as this will increase the pressure acting on the walls. A lower compaction may result in settlement of slab-on-grade floors or other structures supported above the walls. Thus, the compaction level is critical and must be tested by our firm during placement. Surcharges from adjacent footings or heavy construction equipment must be added to the above values. Perimeter footing drains should be provided for all retaining walls, as discussed under the “Drainage Considerations” section of this letter-report. It is imperative that proper drainage be provided so that hydrostatic pressures do not develop against the walls. This would involve installation of a minimum, 1-foot-wide blanket drain to within 1 foot of finish grade for the full wall height using imported, washed gravel against the walls. Pavement Recommendations Pavement areas should be prepared in accordance with the “Site Preparation” section of this letter-report. If the stripped native soil subgrade can be compacted to 95 percent of ASTM D-1557 and is firm and unyielding, no additional preparation is required. Soft or yielding areas should be overexcavated to provide a suitable subgrade and backfilled with structural fill. Dalpay Short Plat Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 9 The exposed ground should be recompacted to a firm and unyielding condition. If required, structural fill may then be placed to achieve desired subbase grades. Upon completion of the recompaction and structural fill, a pavement section consisting of 2½ inches of asphaltic concrete pavement (ACP) underlain by 4 inches of 1¼-inch crushed surfacing base course is the recommended minimum in areas of planned passenger car driving and parking. In driveway areas subjected to heavier loads, such as that from school buses or fire trucks, a minimum pavement section consisting of 3 inches of ACP underlain by 2 inches of 5/8-inch crushed surfacing top course and 4 inches of 1¼-inch crushed surfacing base course is recommended. The crushed rock course must be compacted to 95 percent of the maximum density, as determined by ASTM D-1557. All paving materials should meet gradation criteria contained in the current Washington State Department of Transportation (WSDOT) Standard Specifications. PROJECT DESIGN AND CONSTRUCTION MONITORING We are available to provide additional geotechnical consultation as the project design develops and possibly changes from that upon which this letter-report is based. If the reviewing agency requires the Engineer of Record to review the project during final design and construction, we are available. In this way, our earthwork and foundation recommendations may be properly interpreted and implemented in the design and construction of the project. We are also available to provide geotechnical engineering and monitoring services during construction. The integrity of the building foundations depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of the current scope of work. If these services are desired, please let us know and we will prepare a cost proposal. Da/pay Short P/at Limited Subsurface Exploration Renton, Washington and Geotechnical Engineering Report We have enjoyed working with you on this study and are confident that these recommendations will aid in the successful completion of your project. If you should have any questions, or require further assistance, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Frank S. Mocker, L.G., L.E.G.Matthew A. Miller, P.E. Project Geologist Principal Engineer Attachments:Figure 1:Vicinity Map Figure 2:Site and Exploration Plan Appendix: Exploration Logs April 19, 2019 ASSOCIATED EARTH SCIENCES, INC. FSM/ms - 190165E001-2 - Projects\20190165\KE\WP Page 10 KING COUNTY KING COUNTY May Valley Park Coalfield Park May Creek Park Cougar Mountain Regional Wildland Park NEW C A S T L E RENT O N NEWCASTLE NEWCASTLERENTONRENTONRENTON Copyright:© 2013 National Geographic Society, i-cubed King County 148th Ave SENE 17th St SR 900 RENTON± NOTE: BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION VICINITY MAP PROJ NO. DATE: FIGURE:Document Path: G:\GIS_Projects\aaY2019\VM\190165E001 F1 VM_Dalpay.aprx!( ¥ ¬« SITE 1190165E0014/19 0 20001000 FEET DATA SOURCES / REFERENCES: USGS: 7.5' SERIES TOPOGRAPHIC MAPS, ESRI/I-CUBED/NGS 2013 KING CO: STREETS, CITY LIMITS 1/19, PARCELS 4/19 LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE DALPAY SHORT PLAT RENTON, WASHINGTON DALPAY SHORT PLAT RENTON, WASHINGTON 190165 Dalpay \ 190165E001 F2 Site-Explr.cdrBASE MAP REFERENCE: GOLDSMITH LAND DEVELOPMENT SERVICES, DALPAY SHORT PLAT, PRELIMINARY LOT LAYOUT, 4/10/19 SITE AND EXPLORATION PLAN PROJ NO.DATE:FIGURE: 190165E001 4/19 2 NOTE: BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION. a s s o c i a t e d e a r t h s c i e n c e s i n c o r p o r a t e d FEET 40 800 N NOTE: LOCATION AND DISTANCES SHOWN ARE APPROXIMATE. LEGEND: SITE BOUNDARY EXPLORATION PITEP EP-3 EP-4 EP-5 EP-2 EP-6 EP-1 APPENDIX Grass / Topsoil Vashon Lodgement Till Medium dense, moist, tan silty fine SAND, some gravel; unsorted (SM). Dense, moist, tannish gray, some oxidization, silty fine SAND, some gravel; unsorted (SM). Becomes more sandy. Dense, moist, tannish gray, silty fine to medium SAND, some gravel (SM). Bottom of exploration pit at depth 8.5 feet No seepage. No caving. DESCRIPTION Renton, WA Dalpay Short Plat 1 2 3 4 5 6 7 8 9 10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered. Logged by: AWR Approved by: JHS 4/17/19 Project No. 190165E001 LOG OF EXPLORATION PIT NO. EP-1 Depth (ft)KCTP3 190165.GPJ April 17, 2019 Grass / Topsoil Vashon Lodgement Till Loose to medium dense, tannish brown, silty fine SAND, contains organics (SM). Dense, moist, gray, some oxidation, silty fine SAND, some gravel; unsorted (SM). Dense, moist, gray, silty fine to medium SAND, some gravel; unsorted (SM). Bottom of exploration pit at depth 5.5 feet No seepage. No caving. DESCRIPTION Renton, WA Dalpay Short Plat 1 2 3 4 5 6 7 8 9 10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered. Logged by: AWR Approved by: JHS 4/17/19 Project No. 190165E001 LOG OF EXPLORATION PIT NO. EP-2 Depth (ft)KCTP3 190165.GPJ April 17, 2019 Grass / Topsoil Vashon Lodgement Till Medium dense, moist, tan to tannish gray, silty fine to medium SAND, some gravel (SM). Dense, moist, gray, some oxidation, silty fine SAND, some gravel; unsorted (SM). Contains occasional cobbles. Becomes sandier. Dense, moist, gray, silty fine SAND, some gravel; unsorted (SM). Bottom of exploration pit at depth 8 feet No seepage. No caving. DESCRIPTION Renton, WA Dalpay Short Plat 1 2 3 4 5 6 7 8 9 10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered. Logged by: AWR Approved by: JHS 4/17/19 Project No. 190165E001 LOG OF EXPLORATION PIT NO. EP-3 Depth (ft)KCTP3 190165.GPJ April 17, 2019 Grass / Topsoil Vashon Lodgement Till Medium dense, moist, tan, some oxidation, silty fine SAND, some gravel (SM). Dense, moist, tannish gray to gray, silty fine SAND, some gravel; unsorted (SM). Dense, moist, gray, silty fine SAND; unsorted (SM). Bottom of exploration pit at depth 5 feet No seepage. No caving. DESCRIPTION Renton, WA Dalpay Short Plat 1 2 3 4 5 6 7 8 9 10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered. Logged by: AWR Approved by: JHS 4/17/19 Project No. 190165E001 LOG OF EXPLORATION PIT NO. EP-4 Depth (ft)KCTP3 190165.GPJ April 17, 2019 Grass / Topsoil Vashon Lodgement Till Medium dense, moist, tan, silty fine SAND, some gravel (SM). Dense, moist, tannish gray to gray, some oxidation, silty fine SAND, some gravel; unsorted (SM). Becomes gray, sandier. Bottom of exploration pit at depth 6.5 feet No seepage. No caving. DESCRIPTION Renton, WA Dalpay Short Plat 1 2 3 4 5 6 7 8 9 10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered. Logged by: AWR Approved by: JHS 4/17/19 Project No. 190165E001 LOG OF EXPLORATION PIT NO. EP-5 Depth (ft)KCTP3 190165.GPJ April 17, 2019 Grass / Topsoil Vashon Lodgement Till Medium dense, moist, tan, some oxidation, silty fine SAND, some gravel (SM). Dense, moist, tannish gray, some oxidation, silty fine SAND, some gravel (SM). Becomes less oxidized. Bottom of exploration pit at depth 5.5 feet No seepage. No caving. DESCRIPTION Renton, WA Dalpay Short Plat 1 2 3 4 5 6 7 8 9 10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should beread together with that report for complete interpretation. This summary applies only to the location of this trench at thetime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented area simplfication of actual conditions encountered. Logged by: AWR Approved by: JHS 4/17/19 Project No. 190165E001 LOG OF EXPLORATION PIT NO. EP-6 Depth (ft)KCTP3 190165.GPJ April 17, 2019