Loading...
HomeMy WebLinkAboutEx_08_Geotech_ReportEarthSolutionsNWLLC EarthSolutions NW LLC Geotechnical Engineering Construction Observation/Testing Environmental Services 15365 N.E.90th Street,Suite 100 Redmond,WA 98052 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com GEOTECHNICAL ENGINEERING STUDY HARMONY RIDGE 15509 –116TH AVENUE SOUTHEAST RENTON,WASHINGTON ES-8888 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 PREPARED FOR ICHIJO USA CO., LTD. November 21, 2022 Updated July 3, 2023 _________________________ Samuel E. Suruda, L.G. Senior Staff Geologist _________________________ Chase G. Halsen, L.G., L.E.G. Senior Project Geologist _________________________ Keven D. Hoffmann, P.E. Associate Principal Engineer GEOTECHNICAL ENGINEERING STUDY HARMONY RIDGE 15509 – 116TH AVENUE SOUTHEAST RENTON, WASHINGTON ES-8888 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 07/03/2023 07/03/2023 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this Report Geotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific Times Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project or purpose; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-Dependent The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals’ misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: • confer with other design-team members; • help develop specifications; • review pertinent elements of other design professionals’ plans and specifications; and • be available whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction- phase observations. Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk-management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation. Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 • FAX (425) 449-4711 Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services November 21, 2022 Updated July 3, 2023 ES-8888 Ichijo USA Co., Ltd. 1406 – 140th Place Northeast, Suite 104 Bellevue, Washington 98007 Attention: Kanon Kupferer Greetings, Kanon: Earth Solutions NW, LLC (ESNW) is pleased to present this geotechnical report to support the proposed project. Based on the results of our investigation, the construction of a residential development is feasible from a geotechnical standpoint. Our study indicates the site is underlain by ground moraine deposits (glacial till) that consist primarily of silty sand with gravel, with an isolated area of near-surface fill. Groundwater was not exposed at the test pit locations during the October 2022 exploration. Based on our findings, the proposed single-family residences may be constructed on conventional continuous and spread footing foundations that bear directly on competent native soil, recompacted native soil, or new structural fill that is placed and compacted directly on competent native soil. Native soil conditions considered suitable for support of the proposed structures will likely be encountered beginning at a depth of about two feet below existing grades across most of the property. Areas of existing fill will need to be removed or reworked to establish suitable bearing conditions in proposed structural areas, as recommended by ESNW at the time of construction. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil to the specifications of structural fill or overexcavation and replacement with suitable structural fill will be necessary. From a geotechnical standpoint, full infiltration designs are not recommended for the project due to the widespread prevalence of glacially consolidated soils. The dense to very dense nature of these deposits, in addition to areas of appreciable fine contents, are the primary bases for this opinion. Further discussion of infiltration feasibility is provided within this report. Pertinent geotechnical recommendations are provided in this study. We appreciate the opportunity to be of service to you on this project. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Chase G. Halsen, L.G., L.E.G. Senior Project Geologist DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Table of Contents ES-8888 PAGE INTRODUCTION ................................................................................. 1 General .................................................................................... 1 Project Description ................................................................. 2 SITE CONDITIONS ............................................................................. 2 Surface ..................................................................................... 2 Subsurface .............................................................................. 2 Topsoil and Fill ............................................................. 3 Native Soil and Geologic Setting ................................ 3 Groundwater ................................................................. 3 Geologically Hazardous Areas .............................................. 4 Erosion Hazard ............................................................. 4 Coal Mine Hazard ......................................................... 4 Steep Slopes ................................................................. 5 DISCUSSION AND RECOMMENDATIONS ....................................... 5 General .................................................................................... 5 Site Preparation and Earthwork ............................................. 6 Temporary Erosion Control ......................................... 6 Stripping ....................................................................... 6 Excavations and Slopes .............................................. 7 In-situ and Imported Soil ............................................. 7 Subgrade Preparation .................................................. 8 Structural Fill ................................................................ 8 Foundations ............................................................................ 8 Seismic Design ....................................................................... 9 Slab-on-Grade Floors ............................................................. 10 Retaining Walls ....................................................................... 10 Drainage................................................................................... 11 Infiltration Feasibility ................................................... 11 Preliminary Detention Vault Design ............................ 12 Preliminary Pavement Sections ............................................. 13 Utility Support and Trench Backfill ....................................... 14 LIMITATIONS ...................................................................................... 14 Additional Services ................................................................. 14 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Table of Contents Cont’d ES-8888 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Retaining Wall Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY HARMONY RIDGE 15509 – 116TH AVENUE SOUTHEAST RENTON, WASHINGTON ES-8888 INTRODUCTION General This geotechnical engineering study was prepared for the proposed residential development to be constructed at the United Christian Church campus in Renton, Washington. This study was prepared to provide geotechnical recommendations for currently proposed development plans and included the following geotechnical services:  Test pits to characterize soil and groundwater conditions.  Laboratory testing of representative soil samples collected at the test pit locations.  Geotechnical engineering analyses. The following documents and maps were reviewed as part of the preparation of this study:  Web Soil Survey (WSS), maintained by the Natural Resources Conservation Service under the United States Department of Agriculture (USDA).  Preliminary Utility Map for Harmony Ridge, prepared by Barghausen Consulting Engineers, Inc., dated June 15, 2023.  Geologic Map of the Renton Quadrangle, King County, Washington, prepared by D.R. Mullineaux, 1965.  Soil Survey of the King County Area, Washington, prepared by Dale E. Snyder, Philip S. Gale, and Russell F. Pringle, in association with the USDA SCS, November 1973.  Map of the Seattle Electric Co.’s Renton Coal Mine, Map ID K31, 1919.  Mine Workings from George Watkins Evans’ Report for Renton Coal Company, Map ID K32, 1920.  COR Maps (City of Renton GIS database). DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 2 Updated July 3, 2023 Earth Solutions NW, LLC Project Description The proposed project is currently pursuing construction of 20 single-family residences and associated infrastructure improvements, which will be targeted to the central and southern site areas. The existing church and associated improvements located within the northeast site corner are to remain. Site ingress and egress will be provided via the west edge of 116th Avenue Southeast, with a future potential road extension to the west. Stormwater management is currently proposed via detention within the southwest site corner (Tract A). At the time of report submission, specific building load plans were not available for review; however, based on our experience with similar developments, the proposed residential structures will likely be two stories and constructed using relatively lightly loaded wood framing supported on conventional foundations. Perimeter footing loads will likely be about 2 to 3 kips per lineal foot. Slab-on-grade loading is anticipated to be approximately 150 pounds per square foot (psf). Grade cuts and/or fills of up to about five feet are expected to achieve the design elevation of most lots. More extensive earthwork operations will likely be required to install site utilities and construct the stormwater facility. We understand that a sewer connection will be provided through an easement via the parcel to the northwest of the subject property. If the above design assumptions either change or are incorrect, ESNW should be contacted to review the recommendations provided in this report. ESNW should review the final designs to confirm that appropriate geotechnical recommendations have been incorporated into the plans. SITE CONDITIONS Surface The subject site is located southwest of the intersection between Southeast 16th Street and 116th Avenue Southeast, in Renton, Washington. The approximate site location is depicted on Plate 1 (Vicinity Map) and consists of King County parcel number 202305-9067, totaling a gross site area of about 6.23 acres. The northeast site corner is currently developed with a church and associated improvements. The remaining portions of the site are surfaced with trees and an understory of brush and brambles. Topography generally descends to the south and southwest, with about 25 feet of elevation change occurring within the property confines. Subsurface An ESNW representative observed, logged, and sampled the excavation of 12 test pits within readily accessible areas of the site on October 17, 2022. The test pits ranged in depths from about 8 to 14 feet below the existing ground surface (bgs) and were excavated using a trackhoe and operator retained by ESNW. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please refer to the test pit logs provided in Appendix A for a more detailed description of the encountered subsurface conditions. Representative soil samples collected at the exploration locations were analyzed following the Unified Soil Classification System (USCS) and USDA methods and procedures. Samples were analyzed in our laboratory for moisture content and grain size distribution in general accordance with ASTM procedures. Laboratory test results are provided in Appendix B. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 3 Updated July 3, 2023 Earth Solutions NW, LLC Topsoil and Fill Topsoil was encountered in approximately the upper 6 to 12 inches of existing grades at the test pit locations. The topsoil was characterized by a dark brown color, the presence of fine organic material, and small root intrusions. Based on our observations, an average topsoil thickness of about six inches was encountered at the test locations during the field exploration. Silty sand with gravel fill soil was exposed at TP-4 and observed extending to a depth of about five feet bgs. The fill was characterized by a dense and damp condition at the time of the field exploration. Fill was not encountered at any of the other test pit locations during the October 2022 fieldwork. Native Soil and Geologic Setting Underlying topsoil, native soils were classified primarily as silty sand with gravel (USCS: SM), consistent with local geologic mapping designations of ground moraine deposits (Qgt), otherwise known as glacial till. Variations in soil gradation were locally observed and included areas of increased gravel, silt, and sand contents; however, silty sand with gravel sand should be considered the predominant underlying soil type. Soils within the upper approximate three to five feet of existing grades were generally characterized as medium dense; thereafter, native soils become dense to very dense, extending to the terminus of each test pit location, which occurred between about 8 and 14 feet bgs. An exception occurred at TP-4, where the native soil was characterized as medium dense to the terminus of the test pit. Native soils were primarily observed in a moist condition at the time of the October 2022 fieldwork. The referenced WSS resource indicates the site is underlain by Alderwood gravelly sandy loam (Map Unit Symbol: AgC). This soil series is associated with ridges and hills and is derived from glacial drift. Based on the soil conditions encountered during the subsurface exploration, native soils are considered representative of ground moraine deposits, in accordance with local mapping designations. In our opinion, soil conditions within the off-site easement area will be of similar composition to the soils encountered on site. This opinion is based on review of the referenced WSS and geologic map resources, which depict similar soil conditions (Alderwood gravelly sandy loam and ground moraine deposits) across the easement area. Groundwater Groundwater was not encountered within the explored depths of the test pit locations during the October 2022 exploration. Groundwater seeps are common within glacial deposits, and the elevations and/or flow volumes of seepages can fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater elevations are higher during the winter, spring, and early summer months. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 4 Updated July 3, 2023 Earth Solutions NW, LLC Geologically Hazardous Areas Renton Municipal Code (RMC) 4-3-050 classifies geologically hazardous areas as those areas susceptible to damage relating to sensitive and protected slopes, landslides, erosion, seismic activity, and coal mines. Based on review of COR Maps, the site has been designated as a potential moderate coal mine hazard area. Steep slope areas are depicted on the adjacent property in the area of the proposed sewer easement. Furthermore, based on our review of the RMC, the site is considered to possess low erosion hazard potential. Erosion Hazard RMC 4-3-050G5ci defines a low erosion hazard (EL) as areas with soil characterized as having a slight or moderate erosion potential and a slope less than 15 percent. Based on review of the referenced King County Soil Survey, on-site Alderwood series (AgC) soils are considered to have a moderate erosion potential. As such, the site may be considered to possess a low erosion hazard. A review of the development standards table presented in section 4-3-050G2 indicates there are no required buffers or setbacks associated with EL areas. From a geotechnical standpoint, typical best management practices (BMPs) and permanent landscaping installations can successfully mitigate any potential soil erosion both during and after construction. Coal Mine Hazard COR Maps indicates the subject site is within a moderate coal mine hazard (CM) area. As defined in RMC 4-3-050G5eii, CM areas are defined as areas where mine workings are deeper than 200 feet for steeply dipping seams, or deeper than 15 times the thickness of the seam or workings for gently dipping seams. These areas may be affected by subsidence. Review of the referenced coal mine hazard maps suggests the site is within the vicinity of a historical coal mine operation. However, it appears that mining activity beneath the site area is greater than 200 feet. On this basis, the subject site is considered appropriately mapped within a CM area per the RMC definition. Per the development standards table presented in RMC 4-3- 050G2, there are no code-specified buffers or setbacks for CM areas “based on the results of a geotechnical report and/or independent review.” From a geotechnical standpoint, it is our opinion buffers and/or setbacks need not be applied to the project with respect to the CM area. Construction of the proposed residential development is not expected to increase the potential for ground subsidence on the subject site. This opinion relies on the validity of the information presented in the referenced coal mine maps. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 5 Updated July 3, 2023 Earth Solutions NW, LLC Steep Slopes According to RMC 4-3-050G5a, steep slopes are categorized into two types and are based on identification in the city’s Steep Slope Atlas or another method approved by the city: i. Sensitive Slopes: A hillside, or portion thereof (excluding engineering retaining walls), characterized by: a. An average slope of 25 percent to less than 40 percent. b. An average slope of 40 percent or greater, with a vertical rise of less than 15 feet. c. Abutting an average slope of 25 percent to 40 percent. ii. Protected Slopes: A hillside, or portion thereof, characterized by an average slope of 40 percent or greater grade and having a minimum vertical rise of 15 feet. The referenced COR Maps designates the site and the adjacent easement area as meeting the criteria of sensitive slopes, and the neighboring property is designated as meeting the criteria of both sensitive slopes and protected slopes. Based on review of the referenced utility plan (which depicts baseline survey data), the maximum slope gradients for the subject project are as follows:  Across the subject site, slope averages do not exceed 25 percent over a minimum vertical rise of 15 feet, and there are no slopes that exceed 40 percent over at least 10 feet of vertical rise.  Along the off-site sewer easement, there is at least one slope area with an average grade of approximately 30 percent over a vertical distance of 15 feet. Based on our review, neither sensitive slopes nor protected slopes are present across the subject property per RMC criteria. However, along the off-site sewer easement, at least one area meets the RMC definition of a sensitive slope (but not a protected slope). Per RMC 4-3-050G2, there is no applicable critical area buffer width or structure setback for sensitive slopes unless recommended in a geotechnical report, as a result of independent review, or pursuant to a requirement of the building code and/or official. Based on our understanding of the site geology and competent slope makeup, it is our opinion that buffer and setback distances need not be applied to the proposed off-site sewer easement. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, the construction of the proposed residential development is feasible from a geotechnical standpoint. The primary geotechnical considerations for the proposed development concern structural fill placement and compaction, foundation design, utility installation, and stormwater management design. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 6 Updated July 3, 2023 Earth Solutions NW, LLC Site Preparation and Earthwork Initial site preparation activities will consist of installing temporary erosion control measures, establishing grading limits, and site clearing and stripping activities. Subsequent earthwork activities will involve mass site grading and installation of infrastructure and stormwater management improvements. Temporary Erosion Control The following temporary erosion and sediment control Best Management Practices (TESC BMPs) are offered:  Temporary construction entrances and drive lanes should be constructed with at least six inches of quarry spalls to both minimize off-site soil tracking and provide a stable access entrance surface. A woven geotextile fabric can be placed beneath the quarry spalls to provide greater stability, if needed.  Silt fencing should be placed around the site perimeter.  When not in use, soil stockpiles should be covered or otherwise protected.  Temporary measures for controlling surface water runoff, such as interceptor trenches, sumps, or interceptor swales, should be installed before beginning earthwork activities.  Dry soils disturbed during construction should be wetted to reduce dust.  When appropriate, permanent planting or hydroseeding will help to stabilize site soils. Additional TESC BMPs, as specified by the project civil engineer on the plans, should be incorporated into construction activities. TESC measures will require upkeep and potential modification during construction to ensure proper function; such upkeep should be coordinated with the site erosion control lead, where applicable. Stripping Topsoil was generally encountered in the upper approximately 6 to 12 inches of existing grades at the test pit locations. For stripping estimations, an average topsoil thickness of about six inches can be assumed, based on our field observations. Where encountered, organic-rich topsoil should be stripped and segregated into a stockpile for later use on site or to be exported. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 7 Updated July 3, 2023 Earth Solutions NW, LLC Excavations and Slopes Based on the soil conditions observed at the test pit locations, the following allowable temporary slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The applicable Federal Occupation Safety and Health Administration (OSHA) and Washington Industrial Safety and Health Act (WISHA) soil classifications are also provided:  Loose to medium dense soil 1.5H:1V (Type C)  Areas exposing groundwater seepage 1.5H:1V (Type C)  Dense to very dense, undisturbed native soil 0.75H:1V (Type A) Steeper temporary slope inclinations within undisturbed, very dense native soil may be feasible based on the soil and groundwater conditions exposed within the excavations. ESNW can evaluate the feasibility of utilizing steeper temporary slopes on a case-by-case basis at the time of construction. In any case, an ESNW representative should observe temporary slopes to confirm inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope stability recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Permanent slopes should be graded to 2H:1V (or flatter) and planted with vegetation to enhance stability and minimize erosion potential. Permanent slopes should be observed by ESNW before vegetation and landscaping. In-situ and Imported Soil Successful use of the on-site soil as structural fill will largely be dictated by the moisture content at the time of placement and compaction. Based on the conditions observed during the subsurface exploration, the native soils are considered to possess a moderate to high moisture sensitivity. Depending on the time of year construction occurs, remedial measures (such as soil aeration) may be necessary as part of site grading and earthwork activities. If the on-site soil cannot be successfully compacted, the use of imported soil may be necessary. In our opinion, a contingency should be provided in the project budget for the export of soil that cannot be successfully compacted as structural fill, particularly if grading activities take place during periods of extended rainfall activity. In general, soils with fines contents greater than 5 percent typically degrade rapidly when exposed to periods of rainfall. Imported structural fill soil should consist of well-graded, granular soil that can achieve a suitable working moisture content. During wet weather conditions, imported soil intended for use as structural fill should consist of a well-graded, granular soil with a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three-quarter-inch fraction). DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 8 Updated July 3, 2023 Earth Solutions NW, LLC Subgrade Preparation Foundation and slab subgrade surfaces should consist of competent, undisturbed native soil or structural fill placed and compacted atop competent native soil. ESNW should observe subgrade areas before placing formwork. Supplementary recommendations for subgrade improvement may be provided at the time of construction; such recommendations would likely include further mechanical compaction effort or overexcavation and replacement with suitable structural fill. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, roadway, permanent slope, retaining wall, and utility trench backfill areas. The following recommendations are provided for soils intended for use as structural fill:  Moisture content At or slightly above optimum  Relative compaction (minimum) 95 percent (per ASTM D1557)  Loose lift thickness (maximum) 12 inches Existing site soil may only be considered suitable for use as structural fill if a suitable moisture content is achieved at the time of placement and compaction. If the on-site soil cannot achieve the above specifications, the use of imported structural fill material will likely be necessary. Concerning underground utility installations and backfill, local jurisdictions will likely dictate soil type(s) and compaction requirements. Foundations Based on our findings, the proposed single-family residences may be constructed on conventional continuous and spread footing foundations that bear directly on competent native soil, recompacted native soil, or new structural fill that is placed and compacted directly on competent native soil. Native soil conditions considered suitable for support of the proposed structures will likely be encountered beginning at a depth of about two feet bgs across most of the site. Areas of existing fill (such as at TP-4) will need to be removed or reworked to establish suitable bearing conditions in proposed structural areas, as recommended by ESNW at the time of construction. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil to the specifications of structural fill or overexcavation and replacement with suitable structural fill will be necessary. Provided the foundations will be supported as prescribed, the following parameters may be used for the design:  Allowable soil bearing capacity 2,500 psf  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 9 Updated July 3, 2023 Earth Solutions NW, LLC The above passive pressure and friction values include a factor-of-safety (FOS) of 1.5. A one- third increase in the allowable soil bearing capacity may be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch and differential settlement of about one-half inch is anticipated. Most settlements should occur during construction when dead loads are applied. Seismic Design The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic design, specifically concerning earthquake loads. Based on the soil conditions encountered at the test locations, the parameters and values provided below are recommended for seismic design per the 2018 IBC. Parameter Value Site Class C* Mapped short-period spectral response acceleration, SS (g) 1.407 Mapped 1-second period spectral response acceleration, S1 (g) 0.48 Short period site coefficient, Fa 1.2 Long-period site coefficient, Fv 1.5 Adjusted short-period spectral response acceleration, SMS (g) 1.689 Adjusted 1-second period spectral response acceleration, SM1 (g) 0.72 Design short-period spectral response acceleration, SDS (g) 1.126 Design 1-second period spectral response acceleration, SD1 (g) 0.48 * Assumes very dense soil conditions, encountered to a maximum depth of 14 feet bgs during the October 2022 field exploration, remain very dense to at least 100 feet bgs. Based on our experience with the project geologic setting (glacial till) across the Puget Sound region, soil conditions are likely consistent with this assumption. Further discussion between the project structural engineer, the project owner (or their representative), and ESNW may be prudent to determine the possible impacts on the structural design due to increased earthquake load requirements under the 2018 IBC. ESNW can provide additional consulting services to aid with design efforts, including supplementary geotechnical and geophysical investigation, upon request. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 10 Updated July 3, 2023 Earth Solutions NW, LLC Liquefaction is a phenomenon that can occur within a soil profile as a result of an intense ground shaking or loading condition. Most commonly, liquefaction is caused by ground shaking during an earthquake. Soil profiles that are loose, cohesionless, and present below the groundwater table are most susceptible to liquefaction. During the ground shaking, the soil contracts, and porewater pressure increases. The increased porewater pressure occurs quickly and without sufficient time to dissipate, resulting in water flowing upward to the ground surface and a liquefied soil condition. Soil in a liquefied condition possesses very little shear strength in comparison to the drained condition, which can result in a loss of foundation support for structures. In our opinion, site susceptibility to liquefaction may be considered negligible. The absence of a shallow groundwater table and the dense characteristics of the native soil were the primary bases for this opinion. Slab-on-Grade Floors Slab-on-grade floors for the proposed residential structures should be supported by competent, firm, and unyielding subgrades. Unstable or yielding subgrade areas should be recompacted or overexcavated and replaced with suitable structural fill before slab construction. A capillary break consisting of at least four inches of free-draining crushed rock or gravel should be placed below each slab. The free-draining material should have a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three- quarter-inch fraction). In areas where slab moisture is undesirable, the installation of a vapor barrier below the slab should be considered. Vapor barriers should be made from material specifically designed for use as a vapor barrier and should be installed in accordance with the manufacturer’s recommendations. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters may be used for the design:  Active earth pressure (unrestrained condition) 35 pcf (equivalent fluid)  At-rest earth pressure (restrained condition) 55 pcf  Traffic surcharge* (passenger vehicles) 70 psf (rectangular distribution)  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40  Seismic surcharge 8H psf† * Where applicable. † Where H equals the retained height (in feet). DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 11 Updated July 3, 2023 Earth Solutions NW, LLC The above passive pressure and friction values include a FOS of 1.5 and are based on a level backfill condition and level grade at the wall toe. Revised design values will be necessary if sloping grades are to be used above or below retaining walls. Additional surcharge loading from adjacent foundations, sloped backfill, or other relevant loads should be included in the retaining wall design. Retaining walls should be backfilled with free-draining material that extends along with the height of the wall and a distance of at least 18 inches behind the wall. The upper 12 inches of the wall backfill may consist of less permeable soil, if desired. A sheet drain may be considered instead of using free-draining backfill. A perforated drainpipe should be placed along the base of the wall and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the wall design. Drainage Zones of perched groundwater seepage could develop in site excavations depending on the time of year grading operations take place, particularly within deeper excavations for utilities and stormwater facilities. Temporary measures to control surface water runoff and groundwater during construction would likely involve interceptor trenches, interceptor swales, and sumps. ESNW should be consulted during preliminary grading to both identify areas of seepage and provide recommendations to reduce the potential for seepage-related instability. Finish grades must be designed to direct surface drain water away from structures and slopes. Water must not be allowed to pond adjacent to structures or slopes. In our opinion, foundation drains should be installed along building perimeter footings. A typical foundation drain detail is provided on Plate 4. Infiltration Feasibility From a geotechnical standpoint, full infiltration designs are considered infeasible for the project. The site is predominately underlain by glacially consolidated deposits that consist primarily of silty sand with gravel. As a result of the dense in-situ condition of the native soil and areas of appreciable fines contents, large-scale infiltration implementations would likely exhibit poor to negligible functionality and would not be expected to have suitable long-term performance. Small-scale BMP or LID designs (such as permeable pavement or shallow gravel-filled trenches) may be viable for the project; however, feasibility will largely depend on the grading plan, since any such implementation would need to target the weathered soil horizon located within the upper few feet of existing grades. As such, if significant grade cuts are proposed, small-scale BMP or LID designs will likely not be feasible from a geotechnical standpoint. If desired, ESNW can further evaluate the feasibility of incorporating small-scale BMP or LID designs into the project. If pursued, in-situ infiltration testing will likely be necessary to confirm the feasibility of utilizing such designs and to develop a suitable design infiltration rate. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 12 Updated July 3, 2023 Earth Solutions NW, LLC Preliminary Detention Vault Design We presume that stormwater management will likely be provided via a stormwater detention vault located within the southwestern site corner (Tract A). We anticipate grade cuts of 10 or more feet will be necessary to achieve the subgrade elevation of the vault foundation. Based on our field observations, grade cuts for the vault are likely to expose competent, native glacial till deposits. The vault foundation should be supported directly on very dense native soil or quarry spalls placed directly on competent native soil. The final vault design must incorporate adequate space from property boundaries such that temporary excavations to construct the vault structure may be successfully completed using the recommended temporary slope inclinations provided in this report. Perimeter drains should be installed around the vault and conveyed to an approved discharge point. In our opinion, perched groundwater seepage should be anticipated along the temporary excavation made for construction of the vault; however, buoyancy is not expected to impact the vault design. The following preliminary design parameters may be used for the vault:  Allowable soil bearing capacity 5,000 psf  Active earth pressure (unrestrained) 35 pcf  Active earth pressure (unrestrained, hydrostatic) 80 pcf  At-rest earth pressure (restrained) 55 pcf  At-rest earth pressure (restrained, hydrostatic) 100 pcf  Coefficient of friction 0.40  Passive earth pressure 350 pcf  Seismic surcharge 8H psf* * Where H equals the retained height (in feet). The passive earth pressure and coefficient of friction values include a FOS of 1.5. Vault retaining walls should be backfilled with free-draining material or suitable sheet drainage that extends along the height of the walls. The upper one foot of the wall backfill may consist of a less permeable soil, if desired. A perforated-rigid drainpipe should be placed along the base of the wall and connected to an approved discharge location. If the elevation of the vault bottom is such that gravity flow to an outlet is not possible, the portions of the vault below the drain should be designed to include hydrostatic pressure. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 13 Updated July 3, 2023 Earth Solutions NW, LLC It is our recommendation that ESNW, the owner, and the contractor observe the excavation of a test pit within the vault area prior to excavation activities. The test pit exploration will assist in confirming anticipated soil conditions at the vault subgrade and characterizing seasonal groundwater conditions, which may impact the temporary excavation and grading plan. Preliminary Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications previously detailed in this report. Soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas containing unsuitable or yielding subgrade conditions will require remedial measures, such as overexcavation and/or placement of thicker crushed rock or structural fill sections, before pavement. We anticipate new pavement sections will be subjected primarily to passenger vehicle traffic. For lightly loaded pavement areas subjected primarily to passenger vehicles, the following preliminary pavement sections may be considered:  A minimum of two inches of hot-mix asphalt (HMA) placed over four inches of crushed rock base (CRB).  A minimum of two inches of HMA placed over three inches of asphalt-treated base (ATB). Heavier traffic areas generally require thicker pavement sections depending on site usage, pavement life expectancy, and site traffic. For preliminary design purposes, the following pavement sections for occasional truck traffic and access roadways areas may be considered:  Three inches of HMA placed over six inches of CRB.  Three inches of HMA placed over four-and-one-half inches of ATB. An ESNW representative should be requested to observe subgrade conditions before the placement of CRB or ATB. As necessary, supplemental recommendations for achieving subgrade stability and drainage can be provided. If the on-site roads will be constructed with an inverted crown, additional drainage measures may be recommended to assist in maintaining road subgrade and pavement stability. Final pavement design recommendations, including recommendations for heavy traffic areas, access roads, and frontage improvement areas, can be provided once final traffic loading has been determined. Road standards utilized by the governing jurisdiction may supersede the recommendations provided in this report. The HMA, ATB, and CRB materials should conform to WSDOT specifications, where applicable. All soil base material should be compacted to a relative compaction of 95 percent, based on the laboratory maximum dry density as determined by ASTM D1557. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 14 Updated July 3, 2023 Earth Solutions NW, LLC Utility Support and Trench Backfill In our opinion, the native soil will generally be suitable for the support of utilities. Remedial measures may be necessary for some areas to provide support for utilities, such as overexcavation and replacement with structural fill and/or placement of geotextile fabric. Groundwater seepage may be encountered within utility excavations, and caving of trench walls may occur where groundwater is encountered. Depending on the time of year and conditions encountered, dewatering or temporary trench shoring may be necessary during utility excavation and installation. The native soil is not considered suitable for use as structural backfill throughout the utility trench excavations unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. Moisture conditioning of the soil may be necessary at some locations before use as structural fill. Each section of the utility lines must be adequately supported by the bedding material. Utility trench backfill should be placed and compacted to the structural fill specifications previously detailed in this report or to the applicable specifications of the presiding jurisdiction. LIMITATIONS This study has been prepared for the exclusive use of Ichijo USA Co., Ltd. and its representatives. The recommendations and conclusions provided in this study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. No warranty, express or implied, is made. Variations in the soil and groundwater conditions observed at the test locations may exist and may not become evident until construction. ESNW should reevaluate the conclusions provided in this study if variations are encountered. Additional Services ESNW should have an opportunity to review the final project plans concerning the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked SES Date June 2023 Date 06/30/2023 Proj.No.8888.01 Plate 1 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Vicinity Map Harmony Ridge Renton,Washington Reference: King County,Washington OpenStreetMap.org NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. SITE Renton DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Plate Proj.No. Date Checked DrawnEarthSolutionsNWLLC GeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCMRS NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-8888,Oct.2022 Subject Site Proposed Lot Number 0 1 0 0 2 0 0 Scale in Feet1"=2 0 0 ' SES 06/30/2023 8888.01 2TestPitLocationPlan HarmonyRidgeRenton,WashingtonTP-1 10 TP-1 TP-2 TP-3 TP-4 TP-5TP-6 TP-7 TP-8 TP-10 TP-11 TP-12 TP-9 1 2 3 4 5 67 8 9 10 11 1213 14 15 16 17 18 19 20 116TH AVENUE S.E.S.E. 157THSTREET 118 T H A V E N U E S.E. 21 22 Tract A Tract B Tract C Tract D Sewer Easement S.E. 19 T H S T R E E T DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked SES Date June 2023 Date 06/30/2023 Proj.No.8888.01 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC NOTES: Free-draining Backfill should consist of soil having less than 5 percent fines. Percent passing No.4 sieve should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free-draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Free-draining Structural Backfill 1-inch Drain Rock 18"Min. Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAW ING Retaining Wall Drainage Detail Harmony Ridge Renton,Washington DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked SES Date June 2023 Date 06/30/2023 Proj.No.8888.01 Plate 4 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Slope Perforated Rigid Drain Pipe (Surround in Drain Rock) 18"Min. NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal:native soil or other low-permeability material. 1-inch Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAW ING Footing Drain Detail Harmony Ridge Renton,Washington DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Appendix A Subsurface Exploration Test Pit Logs ES-8888 Subsurface conditions at the subject site were explored on October 17, 2022. Twelve test pits were excavated using a trackhoe and operator retained by ESNW. The approximate locations of the test pits are illustrated on Plate 2 of this study. The test pit logs are provided in this Appendix. The test pits were advanced to a maximum depth of approximately 14 feet bgs. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 >12%Fines<5%FinesHighlyOrganicSoilsSiltsandClaysLiquidLimit50orMoreSiltsandClaysLiquidLimitLessThan50Fine-GrainedSoils-50%orMorePassesNo.200SieveCoarse-GrainedSoils-MoreThan50%RetainedonNo.200SieveSands-50%orMoreofCoarseFractionPassesNo.4SieveGravels-MoreThan50%ofCoarseFractionRetainedonNo.4Sieve>12%Fines<5%FinesGW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Well-graded gravel with or without sand,little to no fines Poorly graded gravel with or without sand,little to no fines Silty gravel with or without sand Clayey gravel with or without sand Well-graded sand with or without gravel,little to no fines Poorly graded sand with or without gravel,little to no fines Silty sand with or without gravel Clayey sand with or without gravel Silt with or without sand or gravel;sandy or gravelly silt Clay of low to medium plasticity;lean clay with or without sand or gravel; sandy or gravelly lean clay Organic clay or silt of low plasticity Elastic silt with or without sand or gravel;sandy or gravelly elastic silt Clay of high plasticity; fat clay with or without sand or gravel;sandy or gravelly fat clay Organic clay or silt of medium to high plasticity Peat,muck,and other highly organic soils EEaarrtthh SSoolluuttiioonnss NNWW LLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services EXPLORATION LOG KEYFillFILLMadeGround Classifications of soils in this geotechnical report and as shown on the exploration logs 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 D2487 and D2488 were used as an identification guide for the Unified Soil Classification System. Terms Describing Relative Density and Consistency Coarse-Grained Soils: Fine-Grained Soils: SPT blows/foot SPT blows/foot Test Symbols &Units Fines =Fines Content (%) MC =Moisture Content (%) DD =Dry Density (pcf) Str =Shear Strength (tsf) PID =Photoionization Detector (ppm) OC =Organic Content (%) CEC =Cation Exchange Capacity (meq/100 g) LL =Liquid Limit (%) PL =Plastic Limit (%) PI =Plasticity Index (%) Component Definitions Descriptive Term Size Range and Sieve Number Smaller than No.200 (0.075 mm) Boulders Modifier Definitions Percentage by Weight (Approx.) <5 5 to 14 15 to 29 >30_ Modifier Trace (sand,silt,clay,gravel) Slightly (sandy,silty,clayey,gravelly) Sandy,silty,clayey,gravelly Very (sandy,silty,clayey,gravelly) Moisture Content Dry -Absence of moisture,dusty,dry to the touch Damp -Perceptible moisture,likely below optimum MC Moist -Damp but no visible water,likely at/near optimum MC Wet -Water visible but not free draining, likely above optimum MC Saturated/Water Bearing -Visible free water,typically below groundwater table Symbols Cement grout surface seal Bentonite chips Grout seal Filter pack with blank casing section Screened casing or Hydrotip with filter pack End cap ATD =At time of drilling Static water level (date) _>50 Density Very Loose Loose Medium Dense Dense Very Dense Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard <4 4 to 9 10 to 29 30 to 49 <2 2 to 3 4 to 7 8 to 14 15 to 29 _>30 EEaarrtthh NNWWLLC EarthSolutions NW LLC Cobbles Gravel Coarse Gravel Fine Gravel Sand Coarse Sand Medium Sand Fine Sand Silt and Clay Larger than 12" 3"to 12" 3"to No.4 (4.75 mm) 3"to 3/4" 3/4"to No.4 (4.75 mm) No.4 (4.75 mm)to No.200 (0.075 mm) No.4 (4.75 mm)to No.10 (2.00 mm) No.10 (2.00 mm)to No.40 (0.425 mm) No.40 (0.425 mm)to No.200 (0.075 mm) DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 5.3 MC = 3.0 MC = 5.5 Fines = 8.7 MC = 10.9 MC = 8.8 Fines = 7.6 OC = 0.8 CEC = 4.8 TPSL SM SP- SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense to dense, damp -becomes dense -probed 2" -becomes weakly cemented Brown poorly graded SAND with silt, loose to medium dense, damp [USDA Classification: slightly gravelly SAND] -becomes medium dense, moist -increasing gravels [USDA Classification: gravelly SAND] Test pit terminated 13.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 6.5 13.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46358 LONGITUDE -122.188 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-1 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 6.8 MC = 4.7 MC = 6.2 TPSL SM SP- SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense, damp -probed 2" -becomes gray, dense -probed 1" -weakly cemented Gray poorly graded SAND with silt and gravel, medium dense, damp Test pit terminated at 11.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 7.5 11.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46387 LONGITUDE -122.18776 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-2 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 4.4 Fines = 36.0 MC = 9.9 MC = 6.1 MC = 4.1 TPSL SM SP- SM Dark brown TOPSOIL, root intrusions to 1.5' Brown silty SAND with gravel, medium dense, damp [USDA Classification: gravelly sandy LOAM] -probed 1" -becomes dense -probed <1" -weakly cemented Brown poorly graded SAND with silt, medium dense, damp Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 9.0 10.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46418 LONGITUDE -122.1872 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-3 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 6.0 MC = 5.8 MC = 4.8 MC = 3.8 TPSL SM SM Dark brown TOPSOIL, shallow root intrusions (Fill) Brown silty SAND with gravel, dense, damp (Fill) -becomes gray, dense pieces -probed <1" -topsoil horizon at 5' Brown silty SAND with gravel, medium dense, damp -weathered soils Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 5.0 10.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46371 LONGITUDE -122.18641 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-4 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 4.4 MC = 9.9 MC = 6.8 Fines = 53.5 MC = 6.4 TPSL SM ML Dark brown TOPSOIL, root intrusions to 3' Brown silty SAND with gravel, medium dense to dense, damp -probed 2" Brown sandy SILT, dense, damp -probed <1" -becomes gray, dense to very dense [USDA Classification: slightly gravelly LOAM] Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 3.5 10.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46325 LONGITUDE -122.18844 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-5 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 6.5 MC = 8.9 MC = 3.2 TPSL SM SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense, damp -probed 1" -becomes gray, weakly cemented -becomes dense Brown silty SAND, dense, moist Test pit terminated at 14.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 1.0 13.0 14.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46336 LONGITUDE -122.18776 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-6 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 3.7 MC = 4.7 OC = 0.7 CEC = 3.0 MC = 6.1 MC = 4.5 Fines = 13.8 TPSL GM SM Dark brown TOPSOIL, root intrusions to 3' Brown silty GRAVEL with sand, medium dense, damp -probed <1" -becomes dense -weakly cemented Brown silty SAND, dense, damp [USDA Classification: gravelly loamy SAND] Test pit terminated at 12.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 6.5 12.0DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46364 LONGITUDE -122.18817 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-7 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 2.9 MC = 4.5 MC = 4.1 Fines = 15.2 MC = 7.2 OC = 0.7 CEC = 3.4 TPSL GM SM Dark brown TOPSOIL, root intrusions to 2' Brown silty GRAVEL with sand, medium dense, damp -probed 1.5" -becomes gray, dense -probed <1" Brown silty SAND with gravel, medium dense, damp [USDA Classification: very gravelly loamy SAND] Test pit terminated at 10.5 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 1.0 7.5 10.5DEPTH(ft)0 5 10 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46361 LONGITUDE -122.18772 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-8 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 7.2 MC = 3.0 TPSL SM Dark brown TOPSOIL, minimal root intrusions Brown silty SAND with gravel, medium dense, damp -becomes gray, dense -weakly cemented Test pit terminated at 8.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 8.0DEPTH(ft)0 5 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46352 LONGITUDE -122.18669 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-9 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 8.6 MC = 9.4 TPSL SM Dark brown TOPSOIL, minimal root intrusions Brown silty SAND with gravel, medium dense, damp -probed 1" -becomes gray, dense -weakly cemented Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 9.0DEPTH(ft)0 5 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46357 LONGITUDE -122.1873 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-10 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 5.0 MC = 12.2 MC = 3.2 TPSL GM SM Dark brown TOPSOIL, minimal root intrusions Brown silty GRAVEL with sand, medium dense, damp -probed <1" Gray silty SAND with gravel, dense, moist -becomes damp Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 4.0 9.0DEPTH(ft)0 5 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46386 LONGITUDE -122.18699 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-11 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 6.8 MC = 5.4 MC = 7.0 TPSL SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense, damp -probed 1.5" -becomes gray, dense -probed <1" -weakly cemented Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 9.0DEPTH(ft)0 5 SAMPLE TYPENUMBEREXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46394 LONGITUDE -122.18649 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-12 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 7/3/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-8888 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 8.7 7.6 36.0 53.5 13.8 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Slightly Gravelly Sand. USCS: SP-SM. USDA: Brown Gravelly Sand. USCS: SP-SM with Gravel. USDA: Brown Gravelly Sandy Loam. USCS: SM with Gravel. USDA: Gray Slightly Gravelly Loam. USCS: Sandy ML. USDA: Brown Gravelly Loamy Sand. USCS: SM. 6 60 PERCENT FINER BY WEIGHTD10 0.232 0.315 0.259 0.362 0.544 0.399 0.156 0.486 GRAIN SIZE DISTRIBUTION 100 4.02 3.45 LL TP-01 TP-01 TP-03 TP-05 TP-07 0.09 0.158 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 4.75 19 37.5 19 19 %Silt 1.65 1.16 TP-01 TP-01 TP-03 TP-05 TP-07 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 7.5ft. 13.0ft. 2.0ft. 5.5ft. 12.0ft. 7.50ft. 13.00ft. 2.00ft. 5.50ft. 12.00ft. PL PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GRAIN SIZE USDA ES-8888 UNITED CHRISTIAN CHURCH PROPERTY.GPJ GINT US LAB.GDT 10/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 15.2 21.8 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Very Gravelly Loamy Sand. USCS: SM with Gravel. USDA: Brown Very Gravelly Sandy Loam. USCS: GM with Sand. 6 60 PERCENT FINER BY WEIGHTD10 0.33 0.266 4.135 9.182 GRAIN SIZE DISTRIBUTION 100 LL TP-08 TP-11 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 37.5 37.5 %Silt TP-08 TP-11 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 8.0ft. 3.0ft. 8.00ft. 3.00ft. PL PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GRAIN SIZE USDA ES-8888 UNITED CHRISTIAN CHURCH PROPERTY.GPJ GINT US LAB.GDT 10/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Report Distribution ES-8888 EMAIL ONLY Ichijo USA Co., Ltd. 1406 – 140th Place Northeast, Suite 104 Bellevue, Washington 98007 Attention: Kanon Kupferer EMAIL ONLY Barghausen Consulting Engineers, Inc. 18215 – 72nd Avenue South Kent, Washington 98032 Attention: Barry Talkington, P.E. Ivana Halvorsen Vicente Varas, P.E. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755