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08_160257E001_R 5-9-17 Edmonds Woodway.pdfa s s o c i a t e d e a r t h s c i e n c e s incorporated Subsurface Exploration and Preliminary Geotechnical Engineering Report EDMONDS WOODWAY HIGH SCHOOL MULTIPURPOSE FIELD IMPROVEMENTS Edmonds, Washington Prepared For: D.A. HOGAN & ASSOCIATES, INC. Project No. 160257E001 May 9, 2017 a s s o c i a t e d earth sciences i n c: o r p 'o r a t e d May 9, 2017 Project No. 160257EO01 D.A. Hogan & Associates, Inc. 119 1st Avenue South, Suite #110 Seattle, Washington 98104 Attention: Mr. Bob Harding Subject: Subsurface Exploration and Preliminary Geotechnical Engineering Report Edmonds Woodway High School Multipurpose Field Improvements 7600 212t" Street SW Edmonds, Washington Dear Mr. Harding: Associated Earth Sciences, Inc. (AESI) is pleased to present the enclosed copies of our geotechnical engineering report for the referenced project. This report summarizes the results of our subsurface exploration and geotechnical engineering studies and offers geotechnical engineering recommendations for the preliminary design of the proposed project. We have enjoyed working with you on this study and are confident that the recommendations presented in this report will aid in the successful completion of your project. Please contact us if you have any questions or if we can be of additional help to you. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington o I Kurt D. Merriman, P.E. Senior Principal Engineer KDM/pc 160257EO01-3 Projects\20160257\KE\WP Kirkland Office 1911 Fifth Avenue I Kirkland, WA 98033 P 1425.827.7701 F 1425.827.5424 Everett Office 12911 % Hewitt Avenue, Suite 2 1 Everett, WA 98201 P 1425.259.0522 F 1 425. 827.5424 Tacoma Office 1 1552 Commerce Street, Suite 102 1 Tacoma, WA 98402 P 1 253.722.2992 F 1253.722.2993 www.aesgeo.com SUBSURFACE EXPLORATION AND PRELIMINARY GEOTECHNICAL ENGINEERING REPORT EDMONDS WOODWAY HIGH SCHOOL MULTIPURPOSE FIELD IMPROVEMENTS Edmonds, Washington Prepared for: D.A. Hogan & Associates, Inc. 119 111 Avenue South, Suite #110 Seattle, Washington 98104 Prepared by: Associated Earth Sciences, Inc. 911 51h Avenue Kirkland, Washington 98033 425-827-7701 Fax: 425-827-5424 May 9, 2017 Project No. 160257EO01 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Project and Site Conditions I. PROJECT AND SITE CONDITIONS 1.0 INTRODUCTION This report presents the results of our subsurface exploration and preliminary geotechnical engineering studies for the proposed Edmonds Woodway High School multipurpose field improvements. The site location is shown on the "Vicinity Map," Figure 1. Existing site features, and the approximate locations of the subsurface explorations referenced in this study are presented on the "Site and Exploration Plan," Figure 2. This report is based on a project concept drawing provided to us by D.A. Hogan & Associates, Inc., the field designer. At the time this report was written, no detailed plans had been formulated for the current athletic field renovations project. 1.1 Purpose and Scope The purpose of this study was to provide subsurface soil and shallow ground water data to be utilized in the preliminary design of the proposed Edmonds Woodway High School multipurpose field improvements. Our study included a review of selected available geologic literature, completing 15 hollow -stem auger soil borings, and performing geologic studies to assess the type, thickness, distribution, and physical properties of the subsurface sediments and shallow ground water. Laboratory testing of grain -size distribution, moisture content, and organic content was completed on selected samples retrieved from the borings and results of the laboratory tests are included in the Appendix. A preliminary geotechnical engineering study was completed to formulate recommendations regarding site preparation, structural fill, subgrade preparation, general recommendations for site drainage design, and foundation design recommendations for new field lights. This report summarizes our current fieldwork and offers development recommendations based on our present understanding of the project. 1.2 Authorization Our study was accomplished in general accordance with our proposal dated March 20, 2017. We were authorized to proceed by means D.A. Hogan & Associates, Inc. This report has been prepared for the exclusive use of D.A. Hogan & Associates, Inc. and its 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 and engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 1 Edmonds Woodway High School Multipurpose Field Improvements Edmonds, Washington 2.0 PROJECT AND SITE DESCRIPTION Subsurface Exploration and Preliminary Geotechnical Engineering Report Project and Site Conditions The project site is that of the existing Edmonds Woodway High School multipurpose fields. Improvements will include major renovations of the existing grass field area southwest of the existing track/field for use as a new synthetic turf baseball/soccer field, re -purposing the area of the existing baseball field for use as a natural turf soccer field, addition of new restrooms and concessions building, as well as resurfaced/additional tennis courts. The work will be phased, and the first phase will be focused on the multipurpose field area. This report focuses primarily on the multipurpose field, but includes subsurface data applicable to later phases of work. On the existing grass field area, existing natural turf will be removed, the field areas will be regraded to approximately elevation 423 feet, subsurface drainage will be installed, and synthetic turf surfacing will be placed. We anticipate excavation cuts faced by a new retaining wall on the order to 7 to 12 feet tall on the west side of the new multipurpose field and fills faced by new retaining walls approximately 7 to 12 feet tall on the east side. Perimeter lighting systems at the new baseball field will be upgraded, including new light poles. We understand that new lighting systems could potentially be installed at the tennis courts as well. Both new fields will occupy approximately the same footprint as those they replace. Four of the existing tennis courts will be resurfaced 3.0 SITE EXPLORATION We completed 15 hollow -stem auger borings at the locations shown on Figure 2. Logs of our borings, labelled EB-1 to EB-15 are included with this report. The borings were completed by advancing a 3-inch inside -diameter, hollow -stem auger with a track -mounted drill rig. During the drilling process, samples were obtained at generally 2.5- to 5-foot-depth intervals. The exploration borings were continuously observed and logged by an engineering geologist from our firm. The various types of soils, as well as the depths where characteristics of the soils changed, are indicated on the exploration logs presented in the Appendix of this report. The exploration logs presented in the Appendix are based on the field logs, drilling action, and inspection of the samples secured. Our explorations were approximately located by measuring from known site features shown on the drawing that was provided to us. Because of the nature of exploratory work, extrapolation of subsurface conditions between field explorations is necessary. Differing subsurface conditions may be present due to the random nature of natural sediment deposition and the alteration of topography by past grading and filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at the time of construction, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 2 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Project and Site Conditions Disturbed, but representative samples were obtained by using the modified Standard Penetration Test (SPT) procedure. This test and sampling method consists of driving a 2-inch outside -diameter, split -barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free -falling a distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance ("N") or blow count. If a total of 50 is recorded within one 6-inch interval, the blow count is recorded as the number of blows for the corresponding number of inches of penetration. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils; these values are plotted on the attached exploration boring logs. The samples obtained from the split -barrel sampler were classified in the field and representative portions placed in watertight containers. The samples were then transported to our laboratory for further visual classification and laboratory testing, as necessary. 4.0 SUBSURFACE CONDITIONS Subsurface conditions on the project site were inferred from the field explorations conducted for this study, visual reconnaissance of the site, and a review of selected applicable geologic literature. As shown on the field logs, many of our exploration borings encountered surficial fill. Observed fill depths are depicted on exploration logs in the Appendix. Below the fill, our exploration borings encountered dense to very dense silty gravelly sand interpreted as lodgement till. 4.1 Stratigraphy Sod and Topsoil Most of the borings encountered existing natural turf approximately 4 to 6 inches thick. Natural turf within the field of play area of the existing baseball field was underlain by a permeable sand base system. Fill All of the 15 exploration borings depicted on Figure 2 encountered existing fill that was observed be up to approximately 14 feet thick. The existing fill was typically loose to medium dense and typically consisted of silty sand with gravel and variable organic content. One should refer to the exploration logs attached with this report for more detailed information regarding the texture, density, and moisture content of the existing fill observed in our explorations. May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 3 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Project and Site Conditions Vashon Lodgement Till All of the 15 exploration borings encountered dense to very dense sand with silt and gravel interpreted as lodgement till sediments. Lodgement till was deposited at the base of an active continental glacier and was subsequently compacted by the weight of the overlying glacial ice. Lodgement till typically possesses high -strength and low -compressibility attributes that are favorable for support of athletic fields and light pole foundations. Lodgement till is silty and moisture -sensitive. In the presence of moisture contents above the optimum moisture content for compaction purposes, lodgement till can be easily disturbed by vehicles and earthwork equipment. Reuse of excavated lodgement till sediments in structural fill applications is feasible if such reuse is explicitly allowed by project specifications, and if the material is dried to achieve a moisture condition such that it can be compacted to a firm and unyielding condition at the specified level of compaction. 4.2 Laboratory Testin We selected two of our exploration boring samples for mechanical grain -size analysis testing. We also selected two of our exploration boring samples for organic content analysis testing. The results of the laboratory analyses are contained in the Appendix. 4.3 Hydrology With the exception of EB-5, ground water was not observed in our explorations. Some minor seepage was encountered at boring location EB-5. We do not expect any significant ground water will be encountered at the time of construction, but shallow perched ground water may be encountered in existing fill where it is underlain by lodgement till. 4.4 Published Geologic Map We reviewed a published geologic map of the area (J.P. Minard, 1983, Geologic Map of Edmonds East and Part of Edmonds West Quadrangles, Washington, U.S. Geological Survey [USGS], Miscellaneous Field Studies Map MF-1541). The referenced map indicates that the site vicinity is characterized by Vashon lodgement till at shallow depths, with advance outwash mapped nearby at slightly lower elevations. 4.5 Slopes Edmonds City Code and Community Development Code, Title 23 addresses critical areas including Geologically Hazardous Areas. The current project will include construction of new athletic field surfacing and associated improvements where similar athletic fields already exist. The areas of planned improvements include slopes on the east and west sides of the new May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc —160257E001-3— Projects �20160257�KE�WP Page 4 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Project and Site Conditions multipurpose field that do not appear to meet City of Edmonds criteria for classification as Landslide Hazard Areas. May 9, 2017 TAG/Pc—160257E001-3 — Projects �20160257� KE� WP ASSOCIATED EARTH SCIENCES, INC. Page 5 Edmonds Woodway High School Multipurpose Field Improvements Edmonds, Washington 5.0 INTRODUCTION Subsurface Exploration and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations II. PRELIMINARY DESIGN RECOMMENDATIONS In our opinion, the proposed field improvements and new light poles are feasible from a geotechnical engineering standpoint, provided that the recommendations contained in this report are incorporated into the design. The existing fill is relatively loose and presents some risk of greater than normal post -construction settlement. The recommendations contained in this report are intended to reduce the potential for post -construction settlement, but not eliminate it. Elimination of all risk of greater than normal post -construction settlement is not expected to be economically feasible due to the depth of the existing fill soils that are potentially prone to consolidation and settlement. The settlement risk mitigation measures recommended in this report are expected to be reasonable to implement and economically viable, but more elaborate settlement risk mitigation measures are possible. We are available to discuss more aggressive settlement risk mitigation strategies and costs on request. The risk of post -construction settlement at this site is difficult to quantify with the existing data, but is expected to be relatively small, on the order of a few inches or less. Grain -size testing completed for this study suggests that subsurface soils at this site can be expected to drain slowly, and therefore, an underdrain system for the new improvements is warranted and storm water infiltration is not recommended. Light pole foundations should be designed with lateral and vertical capacities that are applicable to the materials in which they are embedded. Existing fill will provide less support to light pole foundations than lodgement till. The depth of weaker surficial soils at each light pole location is expected to be different. We are available on request to assist in identification of appropriate soil support parameters to be used at specific light locations when those locations are selected. The restroom and concession building is a potential component of a future phase of construction. This building is located in an area underlain by existing fill. It would be beneficial to site the building in a way that avoids the deepest fill. Fill beneath the building pad should be removed and recompacted. 6.0 EROSION HAZARDS AND MITIGATION The site includes areas that meet City of Edmonds criteria for treatment as Erosion Hazard Areas. The following discussion addresses Washington State Department of Ecology (Ecology) erosion control regulations that will be applicable to the project. We anticipate that if the May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 6 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations project complies with Washington State requirements, it will also be acceptable with respect to City of Edmonds requirements. As of October 1, 2008, Ecology Construction Storm Water General Permit (also known as the National Pollutant Discharge Elimination System [NPDES] permit) requires weekly Temporary Erosion and Sedimentation Control (TESC) inspections and turbidity and pH monitoring for all sites 1 or more acres in size that discharge storm water to surface waters of the state. Because we anticipate that the proposed project will require disturbance of more than 1 acre, we anticipate that these inspection and reporting requirements will be triggered. The following recommendations are related to general erosion potential and mitigation. The erosion potential of the site soils is high. Maintaining cover measures atop disturbed ground typically provides the greatest reduction to the potential generation of turbid runoff and sediment transport. During the local wet season (October 111 through March 31"), exposed soil should not remain uncovered for more than 2 days unless it is actively being worked. Ground -cover measures can include erosion control matting, plastic sheeting, straw mulch, crushed rock or recycled concrete, or mature hydroseed. Project planning and construction should follow local standards of practice with respect to temporary erosion and sedimentation control. Best management practices (BMPs) should include but not be limited to: • Provide storm drain inlet protection; • Route surface water away from work areas; • Keep staging areas and travel areas clean and free of track -out; • Cover work areas and stockpiled soils when not in use; • Complete earthwork during dry weather and site conditions, if possible. 7.0 SITE PREPARATION Fields Site preparation for the renovated fields should include removal of existing structures that will not remain, sod and topsoil, and regrading to establish design subgrade elevation in preparation for the installation of the new underdrains and surfacing. We understand that the new southwest multipurpose field will be regraded to approximately elevation 423 feet. May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 7 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations We recommend that the surface of the subgrade soils exposed after demolition, stripping and regrading be compacted with a smooth -drum, vibratory roller to at least 90 percent of the modified Proctor maximum dry density, as determined by the American Society for Testing and Materials (ASTM) D-1557 test procedure, and to a firm and unyielding surface. Any areas of excessive organic content or excessive moisture should be corrected prior to proof -rolling. Following demolition, stripping, any overexcavation and replacement, and recompaction, all athletic field subgrades should be proof -rolled using a loaded dump truck or other suitable equipment under the observation of the geotechnical engineer. If soft or yielding areas are observed during proof -rolling, additional preparation might be required. Depending upon field conditions at the time of construction, additional preparation could include overexcavation and replacement of yielding soils with structural fill, use of a geotextile fabric, soil cement admixture stabilization, or combinations of these methods. The amount of overexcavation will depend to some degree on the time of year construction occurs, the amount of precipitation during this time, and the amount of care the contractor takes in protecting the exposed subgrade. We recommend that project documents, budgeting, and scheduling include provisions for assessing existing subgrade conditions after proof -rolling, and completion of remedial preparation as appropriate for field conditions at the time of construction. We anticipate that regardless of the time of year earthwork is completed, some amount of overexcavation will be needed. We recommend including a representative amount of overexcavation work in the base bid to encourage competitive pricing. We recommend that the project budget include sufficient funds to complete overexcavation 1 foot thick across the field. If the earthwork for the project will be completed in wet weather and site conditions (typically October to May) winter grading accommodations such as cement treatment and/or additional overexcavation quantities should be included in the base bid. The on -site soils contain a significant amount of fine-grained material, which makes them moderately moisture -sensitive and subject to disturbance when wet. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. It should be noted that the moisture content of the site soils was visually estimated to typically be above the optimum moisture content for compaction purposes at the time of our study. Laboratory moisture content results included in the Appendix also suggest that most of the on -site soils can be expected to be above optimum moisture content for compaction purposes. 7.1 Permanent Cut and Fill Slopes We do not anticipate that significant new permanent cut and fill slopes will be necessary for this project as engineered walls will be constructed in areas of significant elevation change. May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 8 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations However, the following recommendations may be applied to slopes shorter than 8 feet in height. Permanent cut and structural fill slopes should be graded no steeper than 2H:1V (Horizontal:Vertical). Slopes should be hydroseeded as soon as possible after grading. Cut slopes in natural soils that are steeper than 2H:1V may be protected by a rockery up to 4 feet tall or an engineered retaining wall. Rockeries should not be used to face fills unless the fills are reinforced. Unsupported temporary cut slopes into unsaturated existing fill should be made no steeper than 1.5H:1V. Unsupported temporary cuts in unsaturated lodgement till and advance outwash sediments may be planned at 1H:1V or flatter. Actual cut slope angles may have to be adjusted depending upon actual field conditions at the time of construction. 8.0 STRUCTURAL FILL All references to structural fill in this report refer to subgrade preparation, fill type, placement, and compaction of materials, as discussed in this section. Our recommendations for the placement of structural fill are presented in the following sections. 8.1 Fill Placement After stripping, excavation, and any required overexcavation have been performed to the satisfaction of the geotechnical engineer/engineering geologist, the upper 12 inches of exposed ground should be recompacted to 90 percent of the modified Proctor maximum density using ASTM D-1557 as the standard. If the subgrade contains 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 tested and 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 compacted to 90 percent of the modified Proctor maximum density using ASTM D-1557 as the standard. In the case of utility trench filling, the backfill may also need to be placed and compacted in accordance with current local codes and standards. The top of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond the locations of athletic field and pavement edges before sloping down at a maximum angle of 2H:1V. May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 9 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations The contractor should note that any proposed fill soils must be evaluated by Associated Earth Sciences, Inc. (AESI) prior to their use in fills. This would require that we have a sample of the material 72 hours in advance of filling activities 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. The on -site soils contain significant amounts of silt and are considered highly moisture -sensitive. Existing fill was observed to contain topsoil -like organic material in some areas, and excessive organic content is not suitable in structural fill applications. We anticipate that most or all of the existing soils will be wetter than optimum moisture content for compaction purposes and will not be available for reuse in structural fill applications without drying during favorable dry site and weather conditions. The reuse of on -site soils in structural fill applications is contingent on removal of excessive organic material, moisture -conditioning to a moisture content that allows compaction to a firm and unyielding condition at the specified level, and is only permitted if specifically allowed by project plans and specifications. Construction equipment traversing the site when the soils are wet can cause considerable disturbance. 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. 8.2 Subsurface Drains (Underdrains) We recommend that a subsurface drainage system be provided below the new field due to the low permeability of the underlying existing fill and lodgement till sediments. The new underdrain system should consist of perforated pipes placed approximately 15 to 20 feet apart. The pipes should have an invert of at least 12 inches below final grade and be enveloped in washed pea gravel which freely communicates with the field surfacing. We defer to the field designer for specific underdrain requirements and are available to provide geotechnical recommendations related to underdrain design on request. 8.3 Subsurface Drain Trenching Construction of the subsurface drains will require trenching into the underlying sediments and existing fill. As part of this study, borings were advanced to provide preliminary information on sediment density and ease of trenching. The existing fill soils are typically loose to medium dense. Lodgement till sediments will also be encountered and are typically dense to very dense and may contain gravel, cobbles, and occasional boulders. Therefore, the contractor should be May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 10 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations prepared to excavate dense soils and to encounter gravel, cobbles, and occasional boulders during trenching. 8.4 Subfield Drainage Aggregate We anticipate that two layers of drainage aggregate will be placed and compacted over the prepared field subgrade and below the turf. The drainage aggregate is a very specialized manufactured product that provides a compactable, stable working surface while maintaining a high minimum infiltration rate. The drainage aggregate should be tested for gradation and approved by the field designer prior to delivery onsite. Daily sampling and gradation testing during placement is recommended to verify continued compliance with project specifications and approved submittals. The material should be kept moist during transport, placement, and compaction to reduce the potential for fines segregation. Once placed and compacted, the material should be field-tested for density and permeability. If field permeability test results are below the minimum project requirements, the material may need to be loosened and recompacted or removed and replaced with materials that meet the minimum permeability requirements. 9.0 LIGHT POLE FOUNDATIONS We anticipate that light pole foundations for this project will consist of concrete piers cast neat against the sidewalls of drilled holes without the use of forms. 9.1 Vertical Compressive Capacities For this project, we anticipate that lateral capacities will be the most critical design factor for the light pole foundations, and will likely exert the most control over the depth of embedment. Our recommendations for allowable axial compressive capacities are for light pole foundations embedded at least 5 feet below the ground surface and are dependent on the soil type on which the end -bearing is founded. We recommend that the end -bearing portion of the allowable axial compressive capacity be assumed to be 1,500 pounds per square foot (psf) for existing fill or new compacted fill and 10 tons per square foot (tsf) for lodgement till. Vertical capacity can also be achieved through friction along the shafts of the poles, as described below. 9.2 Frictional Resistance For frictional resistance along the shaft of the drilled piers used for light pole foundations, acting both in compression and in uplift, an allowable skin friction value of 250 psf for the existing or new compacted fill is recommended; a value of 500 psf may be used for lodgement May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 11 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations till. We recommended that frictional resistance be neglected in the uppermost 2 feet below the ground surface. The allowable skin friction value includes a safety factor of at least 2.0. 9.3 Lateral Capacities Passive Pressure Method Lateral loads on the proposed light pole foundations, caused by seismic or transient loading conditions, may be resisted by passive soil pressure against the side of the foundation. An allowable passive earth pressure of 200 pounds per cubic foot (pcf), expressed as an equivalent fluid unit weight, may be used for that portion of the foundation embedded within existing fill. A value of 400 pcf may be used in lodgement till. The above values only apply to foundation elements cast "neat" against undisturbed soil. For new structural fill placed around the pier shaft, a passive earth pressure value of 250 pcf is recommended. All fill must be placed as structural fill and compacted to at least 95 percent of ASTM D-1557. Passive values presented are assumed a triangular pressure distribution over 2-pier diameters beginning at the surface and held at a constant depth greater than 8 feet. The triangular pressure distribution is truncated above 2 feet. Light Pole Foundation Construction Considerations In our opinion, the light pole foundation excavations will need to be cased during drilling to facilitate construction and limit caving in the very loose fill soils. The contractor should include temporary casing for the light pole foundation holes in his base bid, in our opinion. Exploration borings suggest that light pole borings may encounter gravel and cobbles. Though not observed in our exploration borings for this project, lodgement till typically contains occasional boulders. The contractor should have the ability to excavate and remove obstacles encountered during light pole foundation drilling, or light pole locations should be shifted to avoid obstacles that are encountered. 10.0 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 report is based. We recommend that AESI perform a geotechnical review of the plans prior to final design completion. In this way, our earthwork and foundation recommendations may be properly interpreted and implemented in the design. We are also available to provide geotechnical engineering and monitoring services during construction. The integrity of the athletic fields and light poles depends on proper site May 9, 2017 ASSOCIATED EARTH SCIENCES, INC. TAG/Pc — 160257EO01-3 — Projects �20160257� KE� WP Page 12 Edmonds Woodway High School Subsurface Exploration and Multipurpose Field Improvements Preliminary Geotechnical Engineering Report Edmonds, Washington Preliminary Design Recommendations 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 this current scope of work. If these services are desired, please let us know, and we will prepare a cost proposal. 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 Tyler A. Gilsdorf, CESCL Staff Geologist lra'66/W. Guenzler, L.E.G. Senior Project Geologist Attachments: Figure 1: Vicinity Map Figure 2: Site and Exploration Plan Appendix: Exploration Logs Laboratory Results May 9, 2017 TAG/pc—160257EO01-3 — Projects J20160257�KE�WP Kurt D. Merriman, P.E. Senior Principal Engineer ASSOCIATED EARTH SCIENCES, INC. Page 13 z a c h l4 ' J J tklei � i • �• `�i� •� '00�. .. muni(y r- All- 1-10 G n • A Jr i1 h c� o! Al -_�—, / ; . •s SITE ate' o i ..• .2• _." � (f:,I• ���'� 1 ..'i'�--• _'` ens • • ��',. Hich Sch 04 565 B'• fm �. iSl I DI2PO,ilATEDl: .... ! �" �• _ J j• .� MOUNTLAK/E I ,%b �i �1�� •�' 1 I TERRACE Uj �' • _ • Q 1 �i'r 'IaLake II,ity, ;cube03NationaGoSdCopyright:02 Snohomish N County A earth sciences 0 A i n c o r p o r a t e d Kitsap King 0 1000 2000 County County VICINITY MAP FEET DATA SOURCES/ REFERENCES: EDMONDS WOODWAY ATHLETIC FIELD IMPROVEMENTS USGS: 24K SERIES TOPOGRAPHIC MAPS NOTE: BLACK AND WHITE SNOHOMISH CO: STREETS, CITY LIMITS, PARCELS 02117 REPRODUCTION OF THIS COLOR EDMON DS, WASHINGTON ORIGINAL MAY REDUCE ITS EFFECTIVENESS AND LEAD TO PROD NO. DATE: FIGURE: LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE INCORRECT INTERPRETATION 160257EO01 1 4/17 1 N A 0 40 80 FEET LEGENDS O EB EXPLORATION BORING CONTOIdR INTERVAL 0.5 . mYi' I 4 i 'rr \ 1 _ / � ' �I I / NOTE! LOCATION AND DISTANCES SHOWN ARE APPROXIMATE. NOTESI . „ I ` \ I / / BASE MAP REFERENCEI D.A. HOGAN, EDMONDS WOODWAY HS MOLTI,PIdRPOSE FIELD, CONCEPT LAYOOT OPTION i P.2, \ I Aj/201i5. I R I r BLACK AND WHITE REPRODbCTION OF THIS COLOR ORIGINAL MAY REDbCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION. ..; � ,. ,� �.� ; •. ; ;,�,, � a s s o c i a t e d earth sciences In c o r p o r a t e d SITE AND EXPLORATION PLAN EDMONDS WOODWAY HIGH SCHOOL LE MONDS, WASHINGTON PROJ NO. DATEi FIGIA 16025IFEOOi' 4/i IF 2 APPENDIX Exploration Logs Laboratory Results U EZ °o Well -graded gravel and Terms Describing Relative Density and Consistency o p o o OW g ravel with sand, little to 2) Density SPT blows/foot w o no fines Very Loose 0 to 4 Coarse-4 to 10 o o o 0 o 0 0 o o o GP Poorly -graded gravel 0)Loose > U) c> o o - v, o �,o w Grained Soils Medium Dense 10 to 30 Test Symbols 0 0 o 0 0 0 o and gravel with sand, Dense 3o to 50 little to no fines Very Dense >50 G = Grain Size M = Moisture Content ° 0° 0 Silty gravel and silty 6 Z C LO o Consistency SPT(2�blows/foot Y A= Atterberg Limits c a S GM gravel with sand Very Soft 0 to 2 C = Chemical Fine - v ~ ` .Soft ° 0 ° 0 2 to 4 DID =Dry Density Grained Soils c E 0 .i Medium Stiff 4 to 8 K = Permeability g o Stiff 8 to 15 Clayey gravel and Very Stiff 15 to 30 N NI GC clayey gravel with sand Hard >30 o L Component Definitions o Well -graded sand and t Descriptive Term Size Range and Sieve Number m SW sand with gravel, little Boulders Larger than 12" o Li u e to no fines Cobbles 3" to 12" m ;n a� _ eveeeveeee Gravel 3" to No. 4 (4.75 mm) Poorly -graded sand con c i °' A SP and sand with gravel, Coarse Gravel 3" to 3/4" Fine Gravel 3/4to No. 4 75 mm " 4 (� ) 4) c cn o v N o little to no fines Sand No. 4 (4.75 mm) to No. 200 (0.075 mm) 0 z Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm) 6 o y � SM Silty Sand and Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm) silty sand with Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm) N v c N o a tp.-::'::. gravel Silt and Clay Smaller than No. 200 (0.075 mm) (3) Estimated Percentage Moisture Content Na sc Clayey sand and co NI clayey sand with gravel Component Percentage by Weight Dry - Absence of moisture, Trace <5 dusty, dry to the touch Slightly Moist - Perceptible Silt, sandy silt, gravelly silt, moisture o ML silt with sand or gravel Some 5 to <12 Moist - Damp but no visible u7 c T w Modifier 12 to <30 water Clay Of low to medium o `—° (silty, sandy, gravelly) Very Moist - Water visible but d CL plasticity; silty, sandy, or not free draining z •= gravelly clay, lean clay Very modifier 30 to <50 Wet -Visible free water, usual) Y NE (silty, sandy, gravelly) from below water table 0- a == Organic clay or silt of low Symbols E — OL plasticity Blows/6" or 0 Sampler portion of 6" Cement grout o Type / i surface seal Elastic silt, clayey silt, silt 2.0" OD Sampler Type o o �, MH with micaceous or Split Spoon p Description (4) Bentonite seal � o or fine sand or Sampler p 3.0" OD Split -Spoon Sampler - :-= Filter pack with A o silt (SPT) 3.25" OD Split -Spoon Ring Sampler (4) . - ; . :: blank casing Clay of high plasticity, v� U o c CH sandy or gravelly Clay, fat Bulk sample 3.0" OD Thin -Wall Tube Sampler section Screened casing 12 E J clay with sand or ravel Y g (including Shelby tube) _ or Hydrotip = with filter pack U c Grab Sample End cap c 9 j % Organic clay or silt of 0 Portion not recovered Jmedium to high (1) (4) Percentage by dry weight Depth of ground water plasticity (2) (SPT) Standard Penetration Test ASTM D 1586 1 ATD = At time of drilling (3) ( ) Q Static water level (date) In General Accordance with w Peat, muck and other rn _0 c a, 0 PT highly organic soils Standard Practice for Description (e) Combined USCS symbols used for and Identification of Soils (ASTM D-2488) fines between 5% and 12% Classifications of soils in this report are based on visual field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and g plasticity estimates and should not be construed to imply field or laboratory testing unless presented herein. Visual -manual and/or laboratory classification 3 methods of ASTM D-2487 and D-2488 were used as an identification guide for the Unified Soil Classification System. T O! ° a s s o c i a t e d earth sciences EXPLORATION LOG KEY FIGURE Al N o i n c o r p o r a t e d a assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-1 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-414 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 44117 4/4117 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q .2-5 a� c o �, 5 Q y Blows/Foot S E T 5 � E 3 ° aai c T o CO to DESCRIPTION C) °m 3 � _ ° 10 20 30 40 Bark / Topsoil Fill Very loose, very moist, dark brown to red brown, silty, fine to medium 4 S-1 SAND, trace gravel, trace organics (SM). 2 A4 2 5 Harder drilling observed at 4.5 feet. 0/ S-2 Very dense, moist, light gray -brown, silty, fine to medium SAND, trace 50/ " gravel; some oxidation (SM). Vashon Lodgement Till Driller noted hard drilling at 7 feet. 10 Very dense, moist, light gray -brown, silty, fine to medium SAND, trace S-3 gravel; unsorted (SM). 19 36 86/12" 0/ " Bottom of exploration boring at 11.5 feet No ground water encountered. 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-2 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-416 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 44117 4/4117 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5 � E 3 ° aai c T o CO to DESCRIPTION C) °m 3 � _ ° 10 20 30 40 Bark / Topsoil Fill Loose, moist, dark brown -gray, silty, fine to medium SAND, trace gravel, S-1 trace organics; low recovery (SM). 6 5 10 5 5 Medium dense, moist, light gray -brown, silty, fine SAND, trace gravel; S-2 zones of oxidation (SM). 4 6 19 13 Vashon Lodgement Till ? Hard drilling observed at 7 feet. Drill cuttings appear till -like. Very hard drilling observed at 9 feet. 10 Very dense, broken rock in sampler, driller noted pounding on rock. 0/1^ S-3 50/1" Bottom of exploration boring at 10 feet No ground water encountered. 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-3 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-416 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 44117 4/4117 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S T 5, E 3 aai T cEo DESCRIPTION C) 3 m ° 10 20 30 40 Grass Turf Fill Loose, moist, light red -brown, silty, fine to medium SAND, trace gravel S-1 (SM). 3 3 5 5 Weathered Vashon Lodgement Till Very dense, moist, light gray -brown, silty, fine SAND, trace gravel; S-2 unsorted; zones of oxidation (SM). 17 28 63 35 10 Vashon Lodgement Till S-3 Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; 29 ag unsorted; broken rock in sampler (SM). p9 ' Bottom of exploration boring at 11.5 feet No ground water encountered. 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-4 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-417 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 44117 4/4117 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5 � E 3 ° aai c T o CO to DESCRIPTION C) °m 3 � _ ° 10 20 30 40 Fill Dense, very moist, light gray -brown, very silty, fine to medium SAND, trace S-1 gravel, trace organics; broken rock in sampler (SM). g 18 A4 28 5 Weathered Vashon Lodgement Till Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; S-2 unsorted; broken rock in sampler (SM). 11 39 AL89 0/ " 10 Vashon Lodgement Till S-3 Very dense, moist, light gray -brown, silty, fine to medium SAND, trace 22 s2 gravel; unsorted (SM). 40 Bottom of exploration boring at 11.5 feet No ground water encountered. 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-5 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-420 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 44117 4/4117 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L ? Q .2-5 a� c o �, 5 Q y 3 Blows/Foot I- aai E S c o T 5, CO to � E T DESCRIPTION C) °m 3 ° 10 20 30 40 Grass Turf Fill Very loose, moist, medium brown -gray, very silty, fine to medium SAND, 2 S-1 trace gravel, trace organics (SM). 2 A3 1 5 Loose, as above. S 2 3 A5 2 10 Medium dense, moist, light gray -brown, silty, fine to medium SAND, trace S-3 gravel (SM). 1 3 11 8 15 -------------------------------- Vashon Lodgement Till 0/ S-4 Driller noted harder drilling at 14.5 feet. 50/ " Very dense, no recovery. S-5 Very dense, no recovery, sampler is wet. 0/ 50/ 20 S-6 Very dense, very moist, light gray -brown, silty, fine SAND, trace gravel; 0/1, unsorted (SM). 50/1" Bottom of exploration boring at 20 feet Possible ground water at 17.5 feet. 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-6 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-423 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5, � E 3 ° aai c T o CO to DESCRIPTION C) °m 3 � _ ° 10 20 30 40 Grass Turf Fill Drill cuttings are light brown with organic matter; drill action is easy. 5 Driller noted harder drilling at 4.5 feet. Dense, moist, light gray -brown, very silty, fine SAND, trace gravel; zones of S-1 oxidation (SM). 6 11 A32 21 Vashon Lodgement Till 10 S-2 Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; 0/ 50/ " unsorted (SM). 15 S-3 Very dense, moist, light gray -brown, silty, fine to medium SAND, trace O/E 50/ " gravel; unsorted (SM). 20 S-4 As above. Broken rock in sampler. O/E 50/ " Bottom of exploration boring at 20.5 feet No ground water encountered. 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-7 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-420 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5, � E 3 ° aai c T o CO to DESCRIPTION C) °m 3 � _ ° 10 20 30 40 Grass Turf Fill Medium dense, moist, light gray -brown, silty, fine to medium SAND, trace S-1 gravel, trace organics; some iron -oxide staining (SM). 23 16 A 8 12 5 As above. S 2 t 15 7 Al2 5 Driller noted harder drilling at 7 feet. 10 Dense, moist, light gray -brown, silty, fine SAND, trace gravel (SM). S-3 11 18 A3 18 Vashon Lodgement Till 15 S-4 Very dense, moist, light gray -brown, silty, fine SAND, trace gravel; 37 Ak87 unsorted (SM). 0/ ° 20 S-5 As above. o/ 50/ " Bottom of exploration boring at 20.5 feet No ground water encountered. 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-8 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-413 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S T 5, � E 3 ° aai cE T `o � CO to DESCRIPTION 6 @ 3 m � _ ° 10 20 30 40 Fill S-1 Medium dense, moist, dark brown -gray, very silty, fine SAND, trace gravel, i Al trace organics; zones of oxidation (SM). g Driller noted hard drilling at 4 feet. 5 Dense, very moist, light gray -brown, silty, fine SAND, trace gravel; zones of S-2 oxidation (SM). 5 15 31 16 Vashon Lodgement Till 10 Very dense, moist, light gray -brown, silty, fine to medium SAND, trace S-3 gravel; unsorted (SM). 31 33 Ak83 0/ " 15 g_4 As above; broken rock in sampler. 34 k5O/4„ 0/ „A 20 S-5 No recovery. 50/ " Bottom of exploration boring at 20.5 feet No ground water encountered. 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-9 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-420 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S T 5, E 3 aai T cEo DESCRIPTION C) 3 m ° 10 20 30 40 Grass Turf Fill Loose, very moist, light gray -brown, very silty, fine to medium SAND, trace S-1 gravel (SM). 5 4 Ag 5 5 Loose, moist, dark brown -gray, silty, fine to medium SAND, trace gravel, S-2 trace organics (SM). 6 5 3 Top 6 inches of sample: Medium dense, moist dark brown, very silty, fine S-3 SAND, some organics, trace gravel (SM). 7 A18 Bottom 12 inches of sample: Medium dense, moist, light gray -brown, very 11 silty, fine to medium SAND, trace gravel; zones of oxidation (SM). 10 Weathered Vashon Lodgement Till Dense, moist, light gray -brown, silty, fine to medium SAND, trace gravel; S-4 unsorted; some minor oxidation (SM). 7 17 8 21 Bottom of exploration boring at 11.5 feet No ground water encountered. 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-10 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-432 Location Edmonds, WA Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q .2-5 a� c o �, 5 Q y 3 Blows/Foot S c E o T 5 CO to � E ° � T DESCRIPTION C) coaai 3 m _ ° 10 20 30 40 Topsoil S-1 Loose, moist, dark brown, very silty, fine SAND, some organics, trace 4 A gravel (SM). 2 5 Fill S-2 Loose, moist, dark brown to red brown, very silty, fine to medium SAND, 2 A4 trace gravel, trace organics (SM). 2 Vashon Lodgement Till Driller noted hard drilling at 8 feet. 10 Very dense, moist, light gray -brown, very silty, fine SAND, some gravel; 13 S-3 unsorted; broken rock in sampler (SM). 36 50/ " 0/ " Observed hard drill action. 15 S-4 Very dense, moist, light gray -brown, very silty, fine to medium SAND, O/E 50/ " some gravel; unsorted; broken rock in sampler (SM). 20 S-5 Very dense, moist, light gray -brown, silty, fine to medium SAND, some 0/ 50/ " gravel; unsorted (SM). 25 S-6 Very dense, no recovery. 0/1^ 50/1" Bottom of exploration boring at 25 feet No ground water encountered. Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-11 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-420 Location Edmonds, WA _ Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L ? Q L o a� c o �, 5 Q y Blows/Foot S E T 5, � E 3 ° aai c T o CO to DESCRIPTION C) ° 3 m � _ ° 10 20 30 40 Fill Medium dense, moist, light gray -brown, very silty, fine SAND, trace gravel 12 S-1 (SM). 10 Ak20 10 5 Weathered Vashon Lodgement Till Very dense, moist, light gray -brown, silty, fine SAND, trace gravel; S-2 unsorted; zones of oxidation (SM). s 25 AL59 34 S-3 O/E 50/ " Vashon Lodgement Till - Very dense, moist, light gray -brown, silty, fine SAND, trace gravel; unsorted (SM). Bottom of exploration boring at 8 feet No ground water encountered. 10 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-12 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-420 Location Edmonds, WA _ Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5, � E 3 ° aai c T o CO to DESCRIPTION C) ° 3 m � _ ° 10 20 30 40 Grass Turf Fill Drill cutting are dark brown with organics, drill action is easy. Driller noted harder drilling at 4 feet. 5 Loose, moist, dark brown -gray, silty, fine to medium SAND, trace gravel, S-1 trace organics; some minor oxidation (SM). 4 6 AL10 4 Weathered Vashon Lodgement Till Medium dense, moist, light gray -brown, silty, fine to medium SAND, trace S-2 gravel; unsorted; zones of oxidation (SM). 8 15 A2 20 10 Vashon Lodgement Till S-3 Very dense, moist, light gray -brown, silty, fine to medium SAND, trace 14 21 54 gravel; unsorted (SM). 33 Bottom of exploration boring at 11.5 feet No ground water encountered. 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-13 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-420 Location Edmonds, WA _ Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q .2-5 a� c o �, 5 Q y Blows/Foot S E T 5, � E 3 ° aai c T o CO to DESCRIPTION C) ° 3 m � _ ° 10 20 30 40 Grass Turf Fill Drill cutting are dark brown with lots of organics, drill action is easy. 5 Loose, very moist, dark brown -gray, silty, fine to medium SAND, trace S-1 gravel, trace organics (SM). 2 2 A 4 Vashon Lodgement Till 10 Dense, moist, light gray -brown, silty, fine SAND, trace gravel; unsorted S-2 (SM). 17 18 A43 25 15 S 3 Very dense, as above (SM). 33 50/ " 20 S-4 As above. 0/ 50/ " Bottom of exploration boring at 20.5 feet No ground water encountered. 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-14 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-423 Location Edmonds, WA _ Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5, � E 3 ° aai c T o CO to DESCRIPTION C) ° 3 m � _ ° 10 20 30 40 Grass Turf Fill Dense, moist, dark brown to red -brown, very silty, fine SAND, trace gravel, S-1 trace organics; low recovery (SM). 12 A3 23 5 Very dense, moist, light red -brown, very silty, fine SAND, trace gravel, 13 S 2 trace organics (SM). 40 50/ " Vashon Lodgement Till 0/ , Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; unsorted (SM). S-3 As above. 32 50/ " Bottom of exploration boring at 8.5 feet No ground water encountered. 10 15 20 25 Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD) assColated Exploration Lo earth s c i en c e s Project Number Exploration Number Sheet Incorporated 160257EO01 EB-15 1of1 Project Name Edmonds Woodway HS Ground Surface Elevation (ft) +/-427 Location Edmonds, WA _ Datum n A Hnnan 11/90115 Driller/Equipment Boretec / Mini -Track Date Start/Finish 4/3/17 4/3/17 Hammer Weight/Drop 140# / 30" Hole Diameter (in) 6 inrhas L Ch Q L o a� c o �, 5 Q y Blows/Foot S E T 5 � E 3 ° c T o CO to DESCRIPTION C) coaai 3 m � _ ° 10 20 30 40 Topsoil S-1 ,_; Loose, moist, dark brown, very silty, fine SAND, some organics, trace 3 gravel (Topsoil). 4 0 --------------------------------- Vashon Lodgement Till 5 Driller noted hard drilling at 4 feet. Very dense, moist light gray -brown, very silty, fine SAND, trace gravel; S-2 unsorted; small zones of oxidation (SM). 10 31 66 35 10 S 3 Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; 21 A L50/E unsorted (SM). o/ 15 S-4 Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; O/E 50/ " unsorted; brown rock in sampler (SM). 20 S-5 Very dense, moist, light gray -brown, very silty, fine SAND, trace gravel; 50/ " unsorted (SM). 25 S-5 As above. 50/ " Bottom of exploration boring at 25.5 feet No ground water encountered. Sampler Type (ST): 2" OD Split Spoon Sampler (SPT) No Recovery M - Moisture Logged by: TAG 3" OD Split Spoon Sampler (D & M) U Ring Sample V Water Level () Approved by: JHS © Grab Sample Shelby Tube Sample 1 Water Level at time of drilling (ATD)