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REVIEWED BLD2023-1355+Geotechnical_Report+10.25.2023_1.27.43_PM+3861031September 29, 2023 ES-9396 Signature Homes by Village Life, LLC 19020 — 33rd Avenue West, Suite 450 Lynnwood, Washington 98036 Attention: Lucas Kragt, P.E. Subject: Geotechnical Evaluation Fulkerson Property 8427 and 8503 — 200t" Street Southwest Edmonds, Washington Greetings, Lucas: Earth Solutionsl N W «C BLD2023-1355 Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services ....,.,... REVIEWED BY CITY OF EDMONDS BUILDING DEPARTMENT; As requested, Earth Solutions NW, LLC (ESNW) has prepared this geotechnical evaluation for the proposed short plat residential development. To complete the geotechnical scope of services, ESNW completed a subsurface exploration, laboratory and engineering analyses, review of the referenced documents, and this letter summarizing our findings and recommendations for the proposed project. Project Description Based on ESNW's understanding of the proposed development, the existing structures will be demolished and the site will be redeveloped with three residential lots, an access road, and associated improvements. Grading plans were not available for review. Given the relatively level nature of the site, we anticipate minimal grading will be required to achieve design elevations. At the time this report was prepared, specific building load values were not available. However, we anticipate the proposed residential structures will consist of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads on the order of 1 to 2 kips per linear foot, column loads of up to about 20 kips, and slab -on -grade loading of 150 pounds per square foot (psf). If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW has reviewed the referenced plans as part of this report preparation. 15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 0 (425) 449-4704 • FAX (425) 449-4711 Signature Homes by Village Life, LLC September 29, 2023 Surface Conditions ES-9396 Page 2 The subject site is located at 8427 and 8503 — 200th Street Southwest in Edmonds, Washington, as illustrated on the attached Vicinity Map (Plate 1). The site consists of two tax parcels (Snohomish County parcel numbers 27041900202900 and 27041900211400) totaling about 0.60 acres. The site is bordered to the north, east, and west by single-family residences, and to the south by 200th Street Southwest. The site is currently developed with two single-family residences, outbuildings, and associated improvements; the remainder of the site consists of grass -covered yard areas with mature trees. Site topography is relatively level with less than five feet of elevation change. Subsurface Conditions An ESNW representative observed, logged, and sampled the excavation of three test pits on August 14, 2023. The test pits were excavated using a trackhoe and operator retained by our firm. The test pits were excavated for purposes of assessing soil conditions, classifying site soils, and characterizing groundwater conditions within the proposed development area. The approximate locations of the test pits are depicted on the attached Test Pit Location Plan (Plate 2). Representative soil samples collected at the explorations locations were analyzed in general accordance with Unified Soil Classification System (USCS) and United States Department of Agriculture (USDA) methods and procedures. Topsoil Where encountered, topsoil was generally observed extending about four inches below the ground surface (bgs). Deeper pockets of topsoil may be encountered locally across the site. The topsoil was characterized by its dark brown color, presence of fine organic material, and small root intrusions. Fill Fill was observed at one of the test pit locations (TP-3) located within the western portion of the subject site. The fill was observed to extend to a depth of roughly two and one-half feet bgs. The fill was characterized primarily as loose and moist silty sand (USCS: SM), and contained bricks, concrete, and wood debris. Fill may also be present within proximity to existing structural improvements. Where encountered, fill soils intended for reuse as structural fill should be free of organics and other deleterious materials, and should be evaluated by ESNW for suitability at the time of construction. Native Soil Underlying existing topsoil and fill, native soil was encountered primarily as silty sand (Unified Soil Classification System: SM), consistent with the typical makeup of glacial till. The near -surface, loose to medium dense deposits may be characterized as "weathered", and the underlying, dense to very dense and cemented deposits may be characterized as "unweathered". The upper, loose to medium dense weathered glacial till deposits were observed generally extending to depths of about two to three feet bgs, transitioning to a dense to very dense, cemented, and unweathered condition at depth. Overall soil relative density generally increased with depth. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Geologic Setting ES-9396 Page 3 Geologic mapping indicates the site is underlain by glacial till deposits (Qvt). As reported on the geologic map resource, the glacial till consists of a nonsorted mixture of silt, sand, pebbles, cobbles, and boulders and commonly is referred to as "hardpan." The till was deposited directly from the glacier as it advanced over bedrock and older Quaternary sediment. Additionally, the Web Soil Survey (WSS) identifies Alderwood-Urban land complex (2 to 8 percent slopes) within the proposed development area. The Alderwood series was formed in glacial till plains. Based on our field observations, on -site native soils are generally consistent with glacial till deposits and Alderwood series soil. Groundwater Groundwater seepage was not observed at the test pit locations during the fieldwork (August 2023). However, seepage should be expected in deeper excavations at this site, particularly during the winter, spring, and early summer months. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. Geologically Hazardous Areas Assessment As part of this geotechnical engineering study, the referenced chapter of the Edmonds City Code (ECC) was reviewed. Based on our investigation and review, there are no geologically hazardous areas present on or adjacent to the site. Geotechnical Considerations Based on our evaluation, the proposed project is feasible from a geotechnical standpoint. The information presented in the following sections is intended to aid site designs and construction. In -situ and Imported Soils On -site soil exposed during site mass grading will likely consist of glacial till. The glacial till is moisture sensitive and may not be suitable for use as structural fill unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. If the on -site soils cannot be successfully compacted, cement treatment and/or the use of an imported soil may be necessary. In our opinion, a contingency should be provided in the project budget for export of soil that cannot be successfully compacted as structural fill if grading activities take place during periods of rainfall activity. We recommend avoiding construction -equipment tracking across the on -site soil and generally active site work during periods of heavy rainfall, as such disturbance has the potential to degrade the on -site soil beyond a workable state. Imported soil intended for use as structural fill should consist of a well -graded, granular soil with a moisture content that is at (or slightly above) the optimum level. 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). Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Wet Season Grading ES-9396 Page 4 If grading takes place during periods of wet weather, a contingency in the project budget should be included to allow for treatment of the on -site soils or export of on -site soils and import of structural fill as described below. Additional surface control and drainage measures will be necessary to control and detain runoff. Stormwater collection tanks may be necessary to detain stormwater. 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: • Structural fill material • Moisture content • Relative compaction (minimum) • Loose lift thickness (maximum) Granular soil* At or slightly above optimum 95 percent (per ASTM D1557) 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. Excavations and Slopes Excavation activities across the site are likely to expose loose to medium dense native soil within the upper approximately two to three feet bgs, transitioning into dense glacial till ("hardpan") with depth. Based on the soil conditions observed at the subsurface 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 and Washington Industrial Safety and Health Act soil classifications are also provided: • Areas exposing groundwater seepage 1.5H:1V (Type C) • Loose soil 1.5H:1 V (Type C) • Medium dense soil 1H:1V (Type B) • Dense to very dense "hardpan" native soil 0.75H:1V (Type A) Earth Solutions NW. LLC Signature Homes by Village Life, LLC ES-9396 September 29, 2023 Page 5 Permanent slopes should be planted with vegetation to enhance stability and to minimize erosion, and should maintain a gradient of 2H:1V or flatter. The presence of perched groundwater may cause localized sloughing of temporary slopes. An ESNW representative should observe temporary and permanent slopes to confirm the slope inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Foundations The proposed residential structures can be supported on conventional spread and continuous footings bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. Provided site earthwork activities are completed in accordance with our recommendations, suitable soil conditions should be exposed in building pad structural subgrade areas. Due to the high moisture sensitivity of the site soils, foundation subgrade areas should be protected from wet weather or areas of remediation should be anticipated; a layer of crushed rock can be considered to protect foundation subgrade areas. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. Provided the structures will be supported as described above, the following parameters can be used for design of the new foundations: • Allowable soil bearing capacity 2,500 psf • Passive earth pressure • Coefficient of friction 300 pcf (equivalent fluid) M1 The passive earth pressure and coefficient of friction values include a safety factor of 1.5. A one- third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch is anticipated, with differential settlement of about one-half inch. The majority of the settlements should occur during construction, as 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 with respect to earthquake loads. Based on the soil conditions encountered at the test pit locations, Site Class D should be used for seismic design. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Liquefaction ES-9396 Page 6 Liquefaction is a phenomenon where saturated, loose, and cohesionless fine sand or silt soil suddenly loses internal strength and behaves as a fluid. This behavior is in response to increased pore water pressures resulting from an earthquake or another intense ground shaking. In our opinion, site susceptibility to liquefaction may be considered negligible. The composition and relatively dense characteristics of the native soil were the primary bases for this opinion. Slab -on -Grade Floors Slab -on -grade floors should be supported on a firm and unyielding subgrade consisting of competent native soil or at least 12 inches of new structural fill. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to construction of the slab. A capillary break consisting of a minimum of four inches of free - draining crushed rock or gravel should be placed below the slab. The free -draining material should have a fines content of 5 percent or less defined as the percent passing the number 200 sieve, based on the minus three-quarters inch fraction. In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If used, the vapor barrier should consist of a material specifically designed to function as a vapor barrier and should be installed in accordance with the manufacturer's specifications. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters may be used for design: • Active earth pressure (unrestrained condition) • At -rest earth pressure (restrained condition) • Traffic surcharge* (passenger vehicles) • Passive earth pressure • Coefficient of friction • Seismic surcharge * Where applicable. t Where H equals the retained height (in feet). 35 pcf (equivalent fluid) 55 pcf 70 psf (rectangular distribution) 300 pcf (equivalent fluid) ME 8H psft The passive earth pressure and coefficient of friction values include a safety factor of 1.5. The above design parameters 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. Earth Solutions NW. LLC Signature Homes by Village Life, LLC ES-9396 September 29, 2023 Page 7 Retaining walls should be backfilled with free -draining material that extends along 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 a less permeable soil, if desired. 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 The presence of groundwater seepage should be expected in excavations. Where zones of groundwater seepage are encountered, temporary measures to control groundwater seepage may be needed. Temporary measures to control groundwater seepage and surface water runoff during construction will likely involve passive elements such as interceptor trenches and sumps, as necessary. Surface water should not be directed to the top or toe of slopes, modular block walls, or rockeries; wall and rockery drainage should not be used to temporarily control surface water during construction. Surface grades must be designed to direct water away from structures and slopes. The grade adjacent to structures and slopes should be sloped away at a gradient of at least 2 percent for a horizontal distance of at least 10 feet or as setbacks allow. In our opinion, perimeter footing drains should be installed at or below the invert of the building footings. A typical footing drain detail is provided on Plate 4 of this report. Infiltration Evaluation In -situ testing was completed in accordance with the Small-scale Pilot Infiltration Test (PIT) procedure, as outlined in Volume III, Chapter 3, Page 526 of the 2014 Stormwater Management Manual for Western Washington (2014 SMMWW). The testing was completed at a depth of approximately four feet at TP-1. The infiltration test was located within undisturbed unweathered glacial till deposits. The measured PIT rate was negligible, with no measurable drop over the course of the test. The very low hydraulic capacity is attributed to both the presence of relatively high in -situ fines content of the native soil and underlying hardpan glacial till which is relatively impermeable. In this respect, infiltration should be considered infeasible for the project. On -site Stormwater Management Pursuant to City of Edmonds stormwater management requirements, implementation of on -site stormwater BMPs are required for proposed developments in accordance with specified thresholds, standards, and lists. The intent of BMP implementation is to infiltrate, disperse, and retain stormwater runoff on site to the extent feasible. The table below summarizes our evaluation of low impact development methods, as outlined in the referenced stormwater manual, from a geotechnical standpoint. It is instructed in the referenced stormwater manual that BMPs are to be considered in the order listed (from top to bottom) for each surface type, and the first BMP that is determined to be viable should be used. For completeness, however, we have evaluated each listed BMP for the proposed surface types. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 ES-9396 Page 8 BMP Viable? Limitations or Infeasibility Criteria Lawns and Landscaped Areas T5.13: Post -construction soil quality Yes None. and depth (Volume V, Chapter 5) Roofs T5.30: Full dispersion (Volume V, Maybe* Adequate vegetative flow paths will likely not be available. Chapter 5) T5.10A: Downspout full infiltration Infeasible due to shallow depth to low permeability hardpan systems (Volume III, Chapter 3) No soil. Roofs T5.10A: Bioretention (Volume V, NO Infeasible due to shallow depth to low permeability hardpan Chapter 7) soil. T5.10B: Downspout dispersion systems (Volume III, Chapter 3) Maybe* Adequate vegetative flow paths are likely not available. Based on proposed grades, the bottom of the perforated stub- T5.10C: Perforated stub -out Maybe* out connection trenches would likely be within the underlying connections (Volume III, Chapter 3) unweathered till, which will likely have perched groundwater during the wet season. T5.30: Full dispersion (Volume V, Maybe* Adequate vegetative flow paths are likely not available. Chapter 5) T5.15: Permeable pavement Infeasible due to shallow depth to low permeability hardpan soil (Volume V, Chapter 5) No which would cause saturation and instability of soil directly supporting the pavement. T5.10A: Bioretention (Volume V, NO Infeasible due to shallow depth to low permeability hardpan Chapter 7) soil. T5.12: Sheet flow dispersion T5.11: Concentrated flow dispersion Maybe* No flooding or erosion impacts are anticipated. However, (Volume V, Chapter 5) adequate vegetative flow paths are likely not available. * Viability stated from a geotechnical standpoint and should be determined by site storm designer with respect to setbacks and flow paths. Utility Support and Trench Backfill The soils observed at the subsurface locations are generally suitable for support of utilities. In general, the soils observed at the test locations will not be suitable for use as structural backfill in the utility trench excavations unless the soil is at or slightly above the optimum moisture content at the time of placement and compaction. If native soil is placed below optimum moisture levels, settlement will likely occur once wet weather impacts the trenches. Native soil will be difficult or impossible to use as utility trench backfill during wet weather conditions. Moisture conditioning or treatment of the soils may be necessary at some locations prior to use as structural fill. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable requirements of presiding jurisdiction. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Limitations ES-9396 Page 9 This letter has been prepared for the exclusive use of Signature Homes by Village Life, LLC and their representatives. No warranty, express or implied, is made. The recommendations and conclusions provided in this letter 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. If the design assumptions outlined in this letter either change or are incorrect, ESNW should be contacted to review the recommendations provided in this letter. The information provided in this letter does not cover unforeseen of changed conditions. Additional Services ESNW should review the final design to verify the geotechnical recommendations provided in this letter have been incorporated into the plans. Additionally, ESNW should be retained to provide observation and testing services during construction, where necessary. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 ES-9396 Page 10 We trust this letter meets your current needs. Should you have questions, or if any additional information is required, please call. Sincerely, EARTH SOLUTIONS NW, LLC Adam Z. Shier, L.G. Project Geologist T. W WA a it 53803 4, O�F`SS��NA ST L 09/29/2023 Henry T. Wright, P.E. Associate Principal Engineer Attachments: Plate 1 — Vicinity Map Plate 2 — Test Pit Location Plan Plate 3 — Retaining Wall Drainage Detail Plate 4 — Footing Drain Detail Test Pit Logs Grain Size Distribution References: • Soil Summary and Preliminary Geotechnical Recommendations, prepared by ESNW, ES- 9396, dated August 23, 2023 • Topographic Survey, provided by the client, dated August 9, 2023 • Geologic Map of the Edmonds East and part of the Edmonds West Quadrangles, Washington, compiled by James P. Minard, dated 1983 • WSS, maintained by the Natural Resources Conservation Service under the USDA. • 2014 SMMWW, prepared by Department of Ecology • Chapter 23.80 (Geologically Hazard Areas), ECC Earth Solutions NW. LLC Perrinville � Q Puget �x 86th Street Southwest X s Sound V 187th Street Southwest l`.s, 111 3 `Due e� 188th Street Southwest ( /Ir1dQlP yPork - '7° 189th Place South N Blake Placen ^ 190th Street Sout Cherry Street Q 191st Street Southwest 192nd Street Southwest J, 3 192nd Place Sou%e5 °a�r'le NOf rhstream / t�ltdole CpP D 193rd Place S Lanouthwest n m �,th place`t'lest lane L _/ Puget ori,e - -- Piyep`9 �196th Street 5--O theses[_ _ _. _ _ _ WA 524 ----- - get_Dr� to - - -- — ^! LanFT e ➢ m „Hindley Lane C viewland Way m o � m A c 3 2 v m ,Z - 199th Street Southwest � n N ^ WA 524 - SITE • 00th Street Southwest Edmond _ DVisfa Place L N 201 st Street Southwest _ College [reel Carol Wa ° 3 202nd Street Southwest 202nd Place Southwest y� 1. > I '3 a' a Edmonds 8 ti y E.a 203rd Street Southwest ZGleo Street Glen Street o r 'o y Lynnwood a Daley scree[ 1.- m Munlbpal a Golf Course Street ' °� Sprague Street > v n y-- o ➢ ^ Pine Ridgej^� -_ S206th Street Southwest -, - -.College Edmonds Street _ park r ^ Place Middle School Main Street _ Main StreeC — " 208th Street Sou a 3 u a °r Map Maple Way ... T O ➢ Maple Street 210th Street Southwest fD Yost Pork ,,'- '�6Pa v Ider Street alnut Street Walnut Street Sher] 3� Cedar Street I 9 Park 212 11 Spruce Street A ~ v Edmonds/ Sweet Woodway Apartments c, so,,,, ^ y 1z f High School Way n'y`' beet 215thSccee[South�es[ ➢ o D m F� r ?Pone Street Chose Lake 216[h Street Southwest 2161h Street Southwest m Elementary WA 99 ^ School 0 < 217th Street Southwest o ❑� ' • / /�c�Q� eec s a v zlacnStreet Southwest Y NORTH Earth i E 'AllN111., Reference:00� Snohomish County, Washington Observation/Testing Open Strell p. org40 Vicinity Map Fulkerson Property Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drawn CAM Date 09/21 /2023 Proj. No. 939E responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked AZS Date Sept. 2023 Plate 1 416 '-I Shed I � i Shed I � — i I House TP-1 � 4 I 'I , I i I TP-3 Driveway I ' House I / I � I i TP-2 Driveway 4161 �hed I 418 200TH STREET S.W. LEGEND TP-1 Approximate Location of — ■ — ESNW Test Pit, Proj. No. ES-9396, Aug. 2023 Subject Site Existing Building 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. NORTH NOT - TO - SCALE Test Pit Location Plan Fulkerson Property Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drawn CAM Date 09/21 /2023 Proj. No. 9396 responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked AZS Date Sept. 2023 Plate 2 18" Min. 0 0 o 0 o O °o o �p � �° �0 .0 po o °o�0 0o0 ° ��o 0 �oo 0 0 0 00° 0000�oo 00000 o 0 0 0 0 oo .0 o, o 8 0 00 o o oo O 0 0 0 0 o o o o O o0 o oo op o° 0 o o 0 0 0 0 o 0 0 0 o0 00° 0 o o 00 0 op oo 0 o o o 0 0 0o Oo 0 0 Oo0o O oo o 00 00 0 0 oo o p o o�oo ...0. 00 0 0 8 0 0 0 0 oo 0 0 0 000 o0 o 000 o 0 0 0 g o Ooop o 0 0o 00 p o oo 0 0 o So o0 0 0 0 0 o 0 0 00 o o 00 0 000 8 Oo 0 & o p 0o0o o Oo .0 0 0�?, 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: Q 00o O p o000 Free -draining Structural Backfill -inch Drain Rock %. of of of ti Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY - NOT TO SCALE NOT A CONSTRUCTION DRAWING Retaining Wall Drainage Detail Fulkerson Property Edmonds, Washington Drawn CAM Date 09/21/2023 Proj. No. 9396 Checked AZS Date Sept. 2023 Plate 3 Perforated Rigid Drain Pipe (Surround in Drain Rock) 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. B.* - _- - - _... " - " 1-inch Drain Rock SCHEMATIC ONLY - NOT TO SCALE NOT A CONSTRUCTION DRAWING Drawn CAM Date 09/21 /2023 Proj. No. 9396 Checked AZS Date Sept. 2023 Plate 4 W I ,1� �� Well -graded gravel with Moisture Content Symbols m CU > GW or without sand, little to 0 c no fines Dry - Absence of moisture, dusty, dry to Cement grout U U j L 11 the touch ATD = At time surface seal 0 O o o of drilling g Bentonite o p o01 00(lo Poorly graded gravel with Damp Perceptible moisture, likely below chips o Z v UU o 0 0 0 GP or without sand, little to optimum MC Static water i LO C o Q�oQ no fines level (date) eall Co ° Moist - Damp but no visible water, likely o a) H a) at/near optimum MC - Filter pack with 65 0 a) tav, 0 0 uD op o GM Silty gravel with or without Wet - Water visible but not free draining, blank casing section o 0 2 � O Q 0 sand likely above optimum MC Screened casing o or Hydrotip with U) ° 0 .0 o Saturated/Water Bearing - Visible free filter pack o U) 0 � Clayey gravel with or water, typically below groundwater table End cap O -0-0 � ° L L LL C7 ^ GC without sand Terms Describing Relative Density and Consistency _ 0 co Z Coarse -Grained Soils: Test Symbols & Units Well -graded sand with u� O SW or without gravel, little to = Density SPT blows/foot Fines Fines Content ( ) oo N o c IL o°o°o°o°o°o °°°°°°°°°°° no fines Very Loose < 4 O LO U ._ U (n o MC =Moisture Content (%) Loose 4 to 9 ':: ca � 0 to , •:: •..:•.;: , . Poorly graded sand with DD = Dr Density cf Medium Dense 10 to 29 Y Y (P ) a)o v Sp or without gravel, little to o Z no fines Dense 30 to 49 Str = Shear Strength (tsf) 0 a)Very Dense _> 50 O U) PID = Photoionization Detector (ppm) co a� '.:' . SM Silty sand with or without o Lo c c :;: .::'•:. ;.. gravel Fine -Grained Soils: OC = Organic Content (%) e . •;. Consistency SPT blows/foot CEC = Cation Exchange Capacity (meq/100 g) : Very Soft < 2 � � SC Clayey sand with or LL = Liquid Limit (%) Soft 2 to 3 ^ without gravel Medium Stiff 4 to 7 PL = Plastic Limit (%) (%) Stiff 8 to 14 PI = Plasticity IndexLO CD Silt with or without sand IVIL or gravel; sandy or Very Stiff 15 to 29 gravelly silt Hard _> 30 0 0 0 U 0 F/// Clay of low to medium Y Component Definitions > a)—.1 plasticity; plasticity; lean clay with cn M t. or without sand or gravel; Descriptive Term Size Range and Sieve Number 00 cn E sandy or gravelly lean clay Boulders Larger than 12" — — _ � rn . — J U .5 Cobbles 3" to 12" �o _ OL Organic clay or silt of Zo — low plasticity Gravel 3" to No. 4 (4.75 mm) -0 to J �_ — Coarse Gravel 3" to 3/4" Fine Gravel 3/4" to No. 4 (4.75 mm) Elastic silt with or without d Sand No. 4 (4.75 mm) to No. 200 (0.075 mm) 0 0 o MH sand or gravel; sandy or Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm) c O (n g gravelly elastic silt Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm) IL 2 >, - Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm) 0 °o U O Clay of high plasticity; Silt and Clay Smaller than No. 200 (0.075 mm) o -0 LO CH fat clay with or without Modifier Definitions o E sand or gravel; sandy or J gravelly fat clay —_ Percentage by fn Weight (Approx.) Modifier CY OH Organic clay or silt of medium to high plasticity < 5 Trace (sand, silt, clay, gravel) 5 to 14 Slightly (sandy, silty, clayey, gravelly) o> ca o PT Peat, muck, and other 15 to 29 Sandy, silty, clayey, gravelly = �U) — = highly organic soils Q _> 30 Very (sandy, silty, clayey, gravelly) 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 ii FILL Made Ground 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. Earth Solutions NW L�c Earth Solutions NWLLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services EXPLORATION LOG KEY Y Earth Solutions NW, LLC TEST PIT NUMBER TP-1 15365 N.E. 90th Street, Suite 100 PAGE 1 OF 1 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property DATE STARTED 8/14/23 COMPLETED 8/14/23 GROUND ELEVATION EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.81816 LONGITUDE-122.34815 LOGGED BY AZS CHECKED BY HTW GROUND WATER LEVEL: NOTES SZ AT TIME OF EXCAVATION SURFACE CONDITIONS Grass AFTER EXCAVATION w _ CL ~Lu _ wJ CO TESTS Q O MATERIAL DESCRIPTION p d7 ry Q Z 0 0.0 TPSL .`=: `. 0.3 Dark brown TOPSOIL Brown silty SAND, loose to medium dense, moist -probed 2" SM GB MC=6.4 20 Gray silty SAND, dense, moist 2.5 -moderately cemented, light iron oxide staining GB MC = 8.6 infiltration test at 4' Fines = 41.3 [USDA Classification: slightly gravelly sandy LOAM] -probed 0-1" 5.0 SM GB MC = 8.2 7.5 GB MC = 10.3 9.0 [USDA Classification: slightly gravelly sandy LOAM] Fines = 39.4 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. J J W d F 2 0] J Q Uj W Z W Y Earth Solutions NW, LLC TEST PIT NUMBER TP-2 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 PAGE 1 OF 1 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property DATE STARTED 8/14/23 COMPLETED 8/14/23 GROUND ELEVATION EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.81792 LONGITUDE-122.34793 LOGGED BY AZS CHECKED BY HTW GROUND WATER LEVEL: NOTES SZ AT TIME OF EXCAVATION SURFACE CONDITIONS Grass AFTER EXCAVATION W _ CL ~W _ wJ CO TESTS Q O MATERIAL DESCRIPTION p d7 ry Q Z 0 0.0 TPSL .`=: `. 0.3 Dark brown TOPSOIL Brown silty SAND, medium dense, moist -probed 1" SM Z. [USDA Classification: very gravelly sandy LOAM] GB MC = 5.3 2.5 Fines = 30.0 3.0 Gray silty SAND, dense, moist -moderately cemented GB MC - 5.3 -probed 0" 5.0 SM GB MC = 9.9 75 9.0 GB MC=6.6 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. Y Earth Solutions NW, LLC TEST PIT NUMBER TP-3 15365 N.E. 90th Street, Suite 100 PAGE 1 OF 1 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property DATE STARTED 8/14/23 COMPLETED 8/14/23 GROUND ELEVATION EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.81810 LONGITUDE-122.34839 LOGGED BY AZS CHECKED BY HTW GROUND WATER LEVEL: NOTES SZ AT TIME OF EXCAVATION SURFACE CONDITIONS Grass AFTER EXCAVATION w _ ~W _ wJ CO TESTS Q O MATERIAL DESCRIPTION p CL ry Q Z 0 0.0 Brown silty SAND with gravel, loose, moist (Fill) -probed 2-3", bricks, concrete, wood SM 12.5 roots 2.5 SM Brown silty SAND, medium dense, moist 3.0 GB MC - 8.7 Gray silty SAND, dense, moist -probed 0-1" -moderately cemented, light iron oxide staining 5.0 GB MC = 9.0 SM 7.5 GB 9.0 MC = 9.6 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. Earth Solutions NW, LLC GRAIN SIZE DISTRIBUTION b..!Rml15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS I HYDROMETER 6 4 3 2 1 5 1 1/2W 3 4 6 810 1416 20 30 40 50 60 100140 200 100 95 90 85 80 75 70 65 H x 60 w � 55 m w 50 z LL 45 z w 40 w a 35 30 25 20 15 10 5 0-11 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS k___ COBBLES GRAVEL SAND SILT OR CLAY fine coarse medium fine