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ENG GEOTECH REPORTGEOTECHNICAL ENGINEERING REPORT MAR-VEL MARBLE REDEVELOPMENT 202 MAIN STREET EDMONDS, WASHINGTON Project No. 1798.01 November 21, 2017 Prepared for: Mary Olsen Prepared b BLPG - i 11 I d7q0PY RECEIVEDZipper(jeo Geoprofessiari IC-Lnts SEP 0 3 2019 � CBUILDING 6 19019 36th Ave West, Suite E I Lynnwood, WA 98036 1 Phone: 425.582.9928 1 'a-4 1 Lipp rGeo Geopi ofessional ConSLI Itants Project Number 1798.01 November 21, 2017 Mary Olsen 16550 76t" Avenue West Edmonds, Washington 98026 Subject: Geotechnical Engineering Report Mar-Vel Marble Redevelopment 202 Main Street Edmonds, Washington Dear Ms. Olsen, In accordance with your request and written authorization, Zipper Geo Associates, LLC (ZGA) has completed the subsurface exploration and geotechnical engineering evaluation for the proposed Mar-Vel Marble Redevelopment project at 202 Main Street in Edmonds, Washington. This report presents the findings of the subsurface exploration and our geotechnical recommendations for the project. Our services were completed in general accordance with our Proposal for Geotechnical Engineering Services (Proposal No. P16278A) dated March 28, 2017. Written authorization to proceed was provided by you on March 28, 2017. In addition to the services presented in proposal P16278A, ZGA also installed groundwater monitoring wells in the geotechnical borings, as authorized by you at the time of exploration. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we may be of further service, please contact us. Sincerely, Zipper Geo Associates LLC JAMES P. GEORGIS James P. Georgis, L.E.G. Principal Copies: Addressee (1) Thomas A. Jones, P.E. Principal 19019 36th Avenue West, Suite E Lynnwood, WA 98036 (425) 582-9928 TABLE OF CONTENTS INTRODUCTION....................................................................................................................... 1 SITEDESCRIPTION.................................................................................................................. 1 PROJECTUNDERSTANDING.................................................................................................. 2 ENVIRONMENTAL CONSIDERATIONS................................................................................... 2 SUBSURFACECONDITIONS................................................................................................... 3 PublishedGeologic Mapping.................................................................................................. 3 SoilConditions....................................................................................................................... 3 GroundwaterConditions......................................................................................................... 5 FieldScreening for VOCs....................................................................................................... 6 Geotechnical Laboratory Testing............................................................................................ 7 CONCLUSIONS AND RECOMMENDATIONS........................................................................... 7 GeneralConsiderations.......................................................................................................... 7 SeismicConsiderations.......................................................................................................... 8 SitePreparation...................................................................................................................... 9 Structural Fill Materials and Placement..................................................................................11 UtilityTrenching and Backfilling.............................................................................................13 Temporary and Permanent Slopes........................................................................................14 TemporarySoldier Pile Shoring.............................................................................................15 ShallowFoundations.............................................................................................................18 PermanentRetaining Walls...................................................................................................19 Slab -on -Grade Floors............................................................................................................20 DrainageConsiderations.......................................................................................................21 CLOSURE................................................................................................................................22 FIGURES Figure 1 —Vicinity Map and Legend Figure 2 — Site and Exploration Plan Figure 3 — Generalized Geologic Cross Section A -A' Figure 4 — Lateral Earth Pressures, Temporary Soldier Pile Wall Figure 5 — Lateral Earth Pressures for Surcharge Loads APPENDICES Appendix A — Subsurface Exploration Procedures and Logs Appendix B — Laboratory Testing Procedures and Results GEOTECHNICAL ENGINEERING REPORT MAR-VEL MARBLE REDEVELOPMENT 202 MAIN STREET EDMONDS, WASHINGTON Project No. 1798.01 November 21, 2017 INTRODUCTION This report documents the surface and subsurface conditions encountered at the site and our geotechnical engineering recommendations for the proposed Mar-Vel Marble Redevelopment project located at 202 Main Street in Edmonds, Washington. The project description, site conditions, and our geotechnical conclusions and design recommendations are presented in the text of this report. Supporting data including detailed exploration logs, field exploration procedures, results of laboratory testing, and other supporting information are presented as appendices. Our geotechnical engineering scope of services for the project included a site reconnaissance, subsurface evaluation, laboratory testing, geotechnical analysis, and preparation of this report. The subsurface evaluation completed for this study included two exploratory borings (B-1/MW-1 and B-2/MW-2) located near the northwest corner and south-central side of the site. Borings B-1 and B-2 extended to respective depths of approximately 35 feet below the existing ground surface. ZGA competed additional borings (B-3/MW-3 through B-9/MW-9) and test pit explorations (TP-1A through TP-4) as part of a Phase II environmental evaluation of the site. These additional explorations have been incorporated into this report. SITE DESCRIPTION The project site is located at 202 Main Street in Edmonds, Washington. The site is bordered to the north by Main Street, to the west by 2nd Avenue South, to the east by an existing alley with commercial buildings further east, and to the south by an existing alley with a gravel parking lot further south. The approximate site location is shown on the enclosed Vicinity Map and Legend, Figure 1. The site supported three conjoined commercial buildings at the time the geotechnical filed investigation (borings B-1/MW-1 and B-2/MW-2) were completed. In general, the three conjoined buildings were constructed along the property lines (zero lot line setback) with the exception of a triangular open -space near the northwest corner of the site and a loading area on the north side of the southern alley. The buildings were one-story with slab -on -grade concrete floors and were reportedly supported on shallow foundations. Prior to ZGA's environmental evaluation of the site, the existing buildings were substantially demolished. Exterior grades around the site slope gently west with a total relief of about 8 feet across the site. The site is generally devoid of vegetation. An existing closed -in -place Underground Storage Tank (UST) is reportedly located below the sidewalk between 2nd Avenue South and the existing site buildings. ZipperGeo C L'O�r FAsli ip- 1 C?'Po W Cants PROJECT UNDERSTANDING Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 We understand the project includes demolition of the existing buildings and construction of a new two-story, mixed -use building with one level of underground parking. We understand that the new development will have roughly the same footprint as the existing structures (about a 1-foot lot -line setback with a few portions of the building set back about 3 to 4 feet). We understand that the new building will utilize shallow foundations with a slab -on -grade parking level concrete floor. Preliminary plans indicate that the below grade parking level and access ramp will be located below the central and western portion of the building with parking level finished floor elevations ranging from about 32.7 to 31 feet. These parking level finished floor elevations are about 5 to 11 feet below existing exterior grades and we anticipate that excavations for foundation elements may extend about 1'/2 to 2 feet deeper for anticipated construction excavation depths of 7 to 13 feet. The eastern 25 feet of the building does not include parking and includes a below grade utility room with a finished floor elevation of 37 feet and a 5-foot diameter stormwater detention pipe with an invert elevation of about 30 feet. The utility room finished floor elevations are about 5 to 7 feet below existing exterior grades and we anticipate that excavations for foundation elements may extend about 1'/2 to 2 feet below the finished floor elevation for anticipated construction excavation depths of 7 to 9 feet, with deeper excavations for the detention pipe. We understand that removal of the offsite closed -in -place underground storage tank is not included in the current development plan, but may be added at a later date depending on City of Edmonds requirements. The proposed development and parking level layout are shown on the enclosed Site and Exploration Plan, Figure 1. ENVIRONMENTAL CONSIDERATIONS The site and nearby vicinity have a documented history of environmental conditions. Environmental documents provided for our review indicate the following. ■ One 1,000-gallon heating oil underground storage tank (UST) was removed from the site. • One below grade hydraulic hoist was removed from the site. • One 1,000-gallon gasoline UST was removed from the off -site gravel parking lot located south of the site. • One 3,000-gallon gasoline off -site UST was closed -in -place below the sidewalk adjacent to the west side of the site. • Approximately 50 tons of petroleum contaminated soil (PCS) was removed from the site, thermally treated, and disposed of offsite. • Approximately 13 tons of PCS was removed from the off -site closed -in -place UST located below the sidewalk adjacent to the west side of the site, thermally treated, and disposed of offsite. • Approximately 131 tons of PCS was removed from the off -site gravel parking lot located south of the site, thermally treated, and disposed of offsite. Petroleum contaminated soils were reportedly present on site at the time of previous remedial actions above MTCA Method A cleanup levels (Chapter 173-340 WAC). Page 2 ZipperGeo GQopro!es "'nil ionwitonts Mar-Vel Marble Redevelopment Project No. 1798.01 November21, 2017 ■ According to the documents, soils exceeding the cleanup standards were not able to be excavated at the time of remedial action and remain in place. • Groundwater was not evaluated from an environmental perspective before, during, or following remedial action. We understand that geotechnical recommendations are needed at this time to move forward with project design and are provided in this report. ZGA has been authorized by the owner to complete a Phase I Environmental Site Assessment (ESA) and a Focused Subsurface Investigation. These environmental services are underway and will be submitted under separate cover. This geotechnical report includes subsurface boring and test pit logs completed as part of our Focused Subsurface Investigation. SUBSURFACE CONDITIONS Published Geologic Mapping We assessed the geologic setting of the site and surrounding vicinity by reviewing the Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, Washington, U.S. Geological Survey Map MF-1541, 1983. The geologic map indicates that the site is underlain by Quaternary Whidbey Formation (Qw) deposits. The Whidbey Formation is generally described as bedded, compact, medium -to -course grained sand with variable silt and gravel content and intermittent peat deposits in the upper portion of the unit. Soil Conditions The subsurface evaluation completed for this project included two borings (B-1/MW-1 and B- 2/MW-2) completed near the south-central side of the site and northwest corner of the site, respectively. Both borings extended to a depth of about 35 feet below grade. ZGA completed additional borings and test pit explorations as part of a Phase II environmental evaluation of the site, which have been incorporated into this report. Phase II borings B-3/MW-3 through B-9/MW-9 extended to depths ranging from about 21 to 28'/z feet below grade. Test pits TP-1 A through TP-4 extended to depths ranging from about 3'/z to 18 feet below grade. Approximate exploration locations are shown on the enclosed Site and Exploration Plan, Figure 1. Soils were visually classified in general accordance with the Unified Soil Classification System. Detailed, descriptive logs of the subsurface explorations and the procedures utilized in the subsurface exploration program are presented in Appendix A. Stratification boundaries on the boring logs represent the approximate depth of changes in soil types, although the transition between materials may have been gradual. The soil types observed in our borings were relatively consistent, but may vary at other locations given limitations to site access for exploration purposes at the time this report was prepared. The nature and extent of variations may not become evident until construction. If variations become apparent during construction, it may be necessary to reevaluate the recommendations of this report. Page 3 ppe r" �G]] eo Mar-Vel Marble Redevelopment Project No. 1798.01 Geopra`-e"londl Ccrsi # ant` November 21, 2017 Generalized descriptions of subsurface soil conditions observed at the exploration locations are presented below. A generalized cross section through the site presenting our interpretation of the subsurface conditions is presented in the enclosed Generalized Cross Section A - A, Figure 3. Please refer to the boring logs in Appendix A for a more detailed description of the conditions encountered at the exploration locations. In general, the explorations encountered concrete pavement/sidewalk over fill soils. Below the fill, native deposits interpreted as weathered glacial till, over glacial till, over glacial advance outwash deposits were encountered. The following table presented a summary stratigraphy of the soils encountered in the exploration followed by a summary description of each soil unit. Summary of Subsurface Conditions Exploration Approx. Ground Surface Elevation 1(ft) Approximate Depth Interval of Soil Unit in Feet Total Depth Explored (ft) Concret a Existing Fill Weathered Glacial Till Glacial Till Glacial Advance Outwash B-1/MW-1 ! 40.88 0 to % %2 to 3%2 3% to 11 11 to 27 27 to 35 35 B-2/MW-2 39.51 0 to %2 %2 to 3% --- 3% to 24 24 to 35 35 B-3/MW-3 41.00 --- --- 0 to 4 4 to 26 26 to 36%z 36% B-4/MW-4 41.32 --- -- -- 0 to 27% 27% to 36%2 36%2 B-5/MW-5 41.20 --- - - 0 to 4 4 to 21% — 21% B-6/MW-6 39.17 --- --- 0 to 4 4 to 30 30 to 38%2 38% B-7/MW-7 39.08 --- - - 0 to 5 5 to 21 - 21 B-8/MW-8 42.62 --- 0 to 5 --- 5 to 21%2 --- 21% B-9/MW-9 40.82 - 0 to 5%2 5% to 21% --- 21% TP-1A 38 --- 0 to 3 3 to 18 18 TP-1B 38 --- --- 0 to 3 3 to 12 --- 12 TP-2A 40 --- 0 to 5%2 --- 5%2 to 10%2 -- 10%2 TP-213 40 0 to 5% --- 5%2 to 10%2 - 10% TP-3 38 --- --- 0 to 3%2 --- -- 3%2 TP-4 43 - - - - 0 to 1'/2 1%2 to 16%2 16%2 1. Ground surface elevations for borings B-1/MW-1 through B-9/1\4W-9 are based on groundwater monitoring well top of monument elevations provided by Pacific Coast Surveys, Inc. Ground surface elevations for test its TP-IA through TP-4 were interpolated from to oy hic contour lines presented on Fi re 2. Existing Concrete Pavement: Borings B-1/MW-1 and B-2/MW-2 were completed through holes cored in existing concrete pavement. The concrete pavement ranged from about 5 to 6 inches thick. Crushed rock was not present below the concrete at the exploration locations. Existing Fill: In general, existing fill soils encountered in the explorations consisted of loose to medium dense, silty sand with some gravel. Former UST cavity backfill was encountered in a portion of test pits TP-2A and TP-213 and consisted of pea gravel. Page 4 Lipp r Mar-Vel Marble Redevelopment 2 r V eo Project No. 1798.01 Geaprnfewicnal Consultants November 21, 2017 Weathered Glacial Till Deposit : Soils interpreted as weathered glacial till generally consisted of medium dense to dense silty sand with variable gravel content. Borings B-1/MW-1 and B-9/MW-9 encountered sandy interbeds within the weathered glacial till at depths of about 4 to 10 feet below grade. Glacial Till Deposits: Soils interpreted as unweathered glacial till were encountered in all of the explorations and were somewhat variable with respect to fines (silt and clay size material) content. In general, the unweathered glacial till consisted of dense to very dense silty sand with some gravel to sand with silt and gravel. This variation in fines content within the unweathered glacial till deposits is depicted in Generalized Cross Section A — A', Figure 3. Glacial Advance autwash Deposits: Soils interpreted as glacial advance outwash generally consisted dense to very dense sand with trace to some silt and gravel. Moderate heave was encountered within the glacial advance outwash deposits in some of the borings. Groundwater Conditions Groundwater was observed in all nine borings and in two of the test pits at the time of exploration. The observed groundwater conditions are interpreted to represent near surface perched groundwater and a deeper groundwater surface. Perched Groundwater: Slight perched groundwater seepage was encountered in boring B-1/MW- 1 at a depth of about 3 feet and in test pits TP-1A and TP1B at a depth of about 4 feet below grade. In boring B-1/MW-1, the groundwater was perched within existing fill soils above lower permeability weathered glacial till deposits. In test pits TP-1A and TP1B, the groundwater was perched in a sand seam in glacial till deposits. Groundwater: Groundwater seepage was encountered in all nine borings at the time of drilling and in subsequent groundwater monitoring well readings, which are presented in the following section. Groundwater depth readings ranged from about 13 to 18 feet below existing grade, or from about elevation 26'/2 feet to 23'/2 feet at the time this report was prepared. In general, groundwater seepage encountered in the borings was rapid once the borings encountered the glacial advance outwash sand deposits at depths of about 24 to 30 feet below grade. At some of the explorations heave was encountered within the glacial advance outwash deposit. Groundwater seepage rates above the glacial advance outwash within the glacial till deposits ranges from very slight to moderate and appear to correspond to the variable fines content (percentage of silt and clay) of the glacial till encountered on site, with slower seepage rates encountered in till soils with higher fines content. Groundwater Monitoring Well Readings: Groundwater monitoring wells were installed in all 9 borings to evaluate fluctuations in groundwater conditions. Monitoring well construction details Page 5 Zp Gpr SrGeo <feWonaictmsulr3no Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 are presented on the boring logs enclosed in Appendix A. Groundwater monitoring well readings are presented in the following table. SUMMARY OF GROUNDWATER MONITORING WELL READINGS Exploration Approximate Ground Surface Elevation (ft) Date Measured 5/22/2017 Approximate groundwater Depth (ft) Approximate Groundwater Elevation (ft) B-1 /MW-1 40.88 14.63 26.25 5/26/2017 14.37 26.51 6/7/2017 14.85 26.03 B-2/MW-2 39.51 5/22/2017 13.18 26.33 5/26/2017 13.88 26.63 6/7/2017 13.20 26.31 10/2/2017 15.56 23.95 B-3/MW-3 41.00 9/14/2017 17.01 23.99 10/2I2017 17.31 23.69 B-4/MW-4 41.32 9/14/2017 17.32 24.00 10/2/2017 17.64 23.68 B-5/MW-5 41.20 9/14/2017 16.50 24.70 10l2/2017 16.86 24.34 B-6/MW-6 39.17 9/14/2017 15.12 24.05 10/2/2017 15.44 23.73 B-7/MW-7 39.08 9/14/2017 14.47 24.61 10/2/2017 14.77 24.31 B-8/MW-8 42.62 9/14/2017 18.03 24.59 10/2/2017 18.42 24.20 B-9/MW-9 40.82 9/14/2017 15.02 25.80 10/2/2017 16.28 24.54 1. Ground surface elevations for borings B-1/MW-1 through B-9/MW-9 are based on groundwater monitoring well top of monument elevations provided by Pacific Coast Surveys, Inc. Groundwater levels, flow rates and soil moisture conditions should be expected to vary throughout the year. Fluctuations of the groundwater levels will likely occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the explorations were performed. Therefore, groundwater levels during construction or at other times in the life of the structure may be higher than indicated on the logs. Groundwater level fluctuations and perched water should be considered when developing the design and construction plans for the project. Field Screening for VOCs Soil samples recovered from the explorations were screened in the field shortly after collection with a hand held Photoionization Detector (PID) to evaluate the presence or absence of Volatile Page 6 "�' Mar-Vel Marble Redevelopment L i p p G-j e o Project No. 1798.01 [aeCpruTpssional Consul~ants November 21, 2017 Organic Compounds (VOCs). PID readings are presented on the exploration logs in Appendix A in parts per million (ppm). Geotechnical Laboratory Testing Geotechnical laboratory testing was completed on select soil samples obtained from the borings. Laboratory testing included moisture content and grain size analysis tests. Due to the suspect presence of petroleum contaminants in the upper portion of boring B-2, our geotechnical tests were primarily completed on samples collected in boring B-1. The results of the moisture content tests are shown on the boring logs. Results for the grain size analyses are provided in Appendix B. In borings B-1, the moisture content of the surficial fill encountered to a depth of about 3'/2 feet was about 13 percent. The moisture content of the underlying weathered and unweathered glacial till deposits encountered between 3'/2 and 25 feet ranged from about 8 to 12 percent. Three grain size analysis tests were completed on samples collected from boring B-1 and considered representative of the weathered and unweathered glacial till deposits and the underlying glacial outwash deposits. The weathered and unweathered glacial till samples collected at depths of 7'/z and 15 feet had fines contents (silt and clay size particles) of about 40 and 46 percent, respectively. The underlying glacial outwash sample collected at a depth of 30 feet had a fines content of about 5 percent. CONCLUSIONS AND RECOMMENDATIONS General Considerations Based on our subsurface exploration program and geotechnical evaluation, we conclude that the proposed project is feasible from a geotechnical standpoint, contingent on proper design and construction practices and implementation of the recommendations presented in this report. Based on our analyses, conventional spread footings and slab -on -grade concrete floors can be used for the new building. Geotechnical engineering recommendations for temporary cuts, temporary shoring, foundations, floor slabs, and other earthwork related phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), engineering analyses, and our current understanding of the proposed project. ASTM and Washington State Department of Transportation (WSDOT) specification codes cited herein respectively refer to the current manual published by the American Society for Testing & Materials and the current edition of the Standard Specifications for Road, Bridge, and Municipal Construction, (M41-10). Page 7 ZI psrGeo GotesSlanrl l Ca Rsu Ita rats Seismic Considerations Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 The development was evaluated relative to seismic hazards resulting from ground shaking associated with the Risk -Targeted Maximum Considered Earthquake (MCER) Ground Motion Response Acceleration and the Maximum Considered Earthquake Geometric Mean (MCEc) Peak Ground Acceleration in accordance with the 2012/2015 International Building Code (IBC). The results of our seismic hazard analyses and recommended seismic design parameters are presented in the following sections. Ground Surface Rupture: We evaluated the potential for seismic ground surface rupture at the site by reviewing the USGS Quaternary Fault Web Mapping Application. The mapping application indicates that there are no mapped Quaternary faults within 5 miles of the site. It is our opinion that the risk of ground surface rupture at the site is low. Landslidin : Based on the relatively level topography of the site and surrounding vicinity, the risk of earthquake -induced landsliding is low. Soil Liquefaction and Lateral Spread _ Liquefaction is a phenomenon wherein saturated cohesionless soils build up excess pore water pressures during earthquake loading. Liquefaction typically occurs in loose soils, but may occur in denser soils if the ground shaking is sufficiently strong. The explorations primarily encountered glacially consolidated glacial till over glacial outwash deposits. Based on the dense to very dense nature of these soils below the groundwater table, it is our opinion that the potential for liquefaction at the site is low. Lateral spreading is a phenomenon in which soil deposits which underlie a site can experience significant lateral displacements associated with the reduction in soil strength caused by soil liquefaction. This phenomenon tends to occur most commonly at sites where the soil deposits can flow toward a "free -face", such as a water body. Due to the lack of liquefiable soils at the site and the lack of a nearby "free -face" condition, it is our opinion that the risk of lateral spreading at the site is low. IBC Seismic Design Parameters: 2012/2015 IBC Seismic Design parameters are summarized on the table below. Code Used 2012/2015 International Building Code (IBC) Ss Spectral Acceleration for a Short Period S, Spectral Acceleration for a 1-Second Period Fa Site Coefficient for a Short Period F Site Coefficient for a 1-Second Period Sees Maximum considered spectral response acceleration for a Short Period Site Classification Cz 1.270g (Site Class B) 0.498g (site Class B) 1.000 (Site Class C) 1.302 (Site Class C) 1.270g (Site Class C) Page 8 Zipp Genprofesslorwl Consrflnws Code Used Sri, Maximum considered spectral response accese fora 1-Second Period Sos Five -percent damped design spectral response acceleration for a Short Period Soi Five -percent damped design spectral response acceleration for a 1-Second Period Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 Site Classification 0.648g (Site Class C) 0.847g (Site Class C) 0.432g (Site Class C) 1. In general accordance with the 201212015 International Building Code, Section 1613.3.2 and ASCE 7-10, Chapter 20. IBC Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2. The borings completed for this study extended to a maximum depth of 35 feet below grade. ZGA therefore determined the Site Class assuming that dense to hard glacially over -consolidated soils extend to 100 feet as suggested by published geologic males for the project area. Site Preparation Existing Structure Removal: At the time this report was prepared, the three site buildings had been substantially demolished. However, portions of the foundations or other below grade structures may be present at currently undisclosed locations. We recommend that all existing foundation elements or other structures be demolished and removed from the proposed building area. Existing Utility Removal: We recommend that all underground utilities within the building pad be completely removed. Utility pipes outside the building envelope that are not used for the new development are expected to be located within the City of Edmonds right-of-way given the close proximity of the building envelope to property lines. Utility abandonment in the right-of-way should be completed in accordance with City of Edmonds requirements. Erosion Control Measures: Stripped surfaces and soil stockpiles are typically a source of runoff sediments. We recommend that silt fences, berms, straw waddles, and/or swales be installed around the downslope side of stripped areas and stockpiles in order to capture runoff water and sediment. If earthwork occurs during wet weather, we recommend that soil stockpiles be protected with anchored plastic sheeting. Temporary Drainage: Stripping, excavation, grading, and subgrade preparation should be performed in a manner and sequence that will provide drainage at all times and provide proper control of erosion. The near -surface site soils have a moderate to high fines (silt and clay) content and are therefore highly susceptible to disturbance and erosion when wet. The site should be graded to prevent water from ponding in construction areas and/or flowing into and/or over excavations. Exposed grades should be crowned, sloped, and smooth -drum rolled at the end of each day to facilitate drainage if inclement weather is forecasted. Accumulated water must be removed from subgrades and work areas immediately and prior to performing further work in the area. Equipment access may be limited and the amount of soil rendered unfit for use as structural fill may be greatly increased if drainage efforts are not accomplished in a timely manner. Successful drainage of saturated zones due to accumulations of surface water would be relatively Page 9 Mar-Vel Marble Redevelopment Z ir� eo Project No. 1798.01 S.,c-anrafrss3onat cof'. 4L lnts November 21, 2017 slow due to the fines content of the surficial soils. Instead, aeration or removal and replacement would be more expeditious. Runoff from the existing paved areas around the site should not be allowed to flow into excavation areas. We recommend that asphalt berms or sandbags be used to divert runoff around the excavation areas to a suitable discharge location. Clearing and Stripping: We anticipate that clearing and stripping will be limited to the removal of a few existing ornamental plantings on the north side of the building, as well as any underlying organic -rich topsoil. We anticipate that stripping depths will vary from about 6 to 12 inches in planter areas. Subgrade Preparation: Once site preparation is complete, all areas that do not require over - excavation and are at design subgrade elevation or areas that will receive new structural fill should be compacted to a firm and unyielding condition. Some moisture conditioning of site soils may be required to achieve a moisture content appropriate for compaction. This is generally within ±2 percent of the soils optimum moisture content. In our opinion, earthwork should be completed during drier periods of the year when soil moisture content can be controlled by aeration and drying. If earthwork or construction activities take place during extended periods of wet weather, or if the in -situ moisture conditions are elevated above the optimum moisture content, the soils could become unstable or not be compactable. In the event the exposed subgrade becomes unstable, yielding, or unable to be compacted due to high moisture conditions, we recommend that the materials be removed to a sufficient depth in order to develop stable subgrade soils that can be compacted to the minimum recommended levels. The severity of construction problems will be dependent, in part, on the precautions that are taken by the contractor to protect the subgrade soils. Once compacted, subgrades should be evaluated by a geotechnical engineer through visual observation, density testing, and proof rolling if the building excavation is accessible with heavy rubber -tired construction equipment given site access to assess the subgrade adequacy and to detect soft and/or yielding soils. In the event that compaction fails to meet the specified criteria, the upper 12 inches of subgrade should be scarified and moisture conditioned as necessary to obtain at least 95 percent of the maximum laboratory density (per ASTM D1557). Those soils which are soft, yielding, or unable to be compacted to the specified criteria should be over - excavated and replaced with suitable material as recommended in the Structural Fill section of this report. Alternatively, over -optimum soils could be treated with cement as a method to stabilize and strengthen soft, wet soils. To protect stable subgrades, either inside or outside the building excavation, we recommend using crushed rock or crushed recycled concrete. The thickness of the protective layer should be determined at the time of construction and be based on the moisture condition of the soil and the amount of anticipated construction traffic. Page 10 Z i p p� rG ea Mar-Vel Marble Redevelopment Project No. 1798.01 ,��p� ':sslonaiNovember21, 2017 Freezing Conditions: If earthwork takes place during freezing conditions, all exposed subgrades should be allowed to thaw and then be compacted prior to placing subsequent lifts of structural fill. Alternatively, the frozen material could be stripped from the subgrade to expose unfrozen soil prior to placing subsequent lifts of fill or foundation components. The frozen soil should not be reused as structural fill until it is allowed to thaw and adjusted to the proper moisture content, which may not be possible during winter months. Structural Fill Materials and Placement Structural fill includes any material placed below foundations and pavement sections, within utility trenches, and behind retaining walls. Prior to the placement of structural fill, all surfaces to receive fill should be prepared as previously recommended in the Site Preparation section of this report. Laborato Testin : Representative samples of on -site and imported soils to be used as structural fill should be submitted for laboratory testing at least 4 days in advance of its intended use in order to complete the necessary Proctor tests. Re -Use of Site Soils as Structural Fill: It is our opinion that the site glacial till soils typically consisting of silty sand with variable gravel content are suitable for reuse as general structural fill from a compositional standpoint provided it is placed and compacted in accordance with the recommendations presented in this report. The reuse of site soils as structural fill during wet weather will be much more difficult. We recommend that site soils used as structural fill have less than 4 percent organics by weight and have no woody debris greater than '/2 inch in diameter. We recommend that all pieces of organic material greater than'/ inch in diameter be picked out of the fill before it is compacted. Any organic -rich soil and high plasticity clay derived from earthwork activities should be utilized in landscape areas or wasted from the site. Imported Structural Fill: Imported structural fill may be required due to weather or other reasons. The appropriate type of imported structural fill will depend on weather conditions. During extended periods of dry weather, we recommend imported fill meet the requirements of Common Borrow as specified in Section 9-03.14(3) of the 2016 Washington State Department of Transportation, Standard Specifications for Road, Bridge, and Municipal Construction (WSDOT Standard Specifications). During wet weather, higher -quality structural fill might be required, as Common Borrow may contain sufficient fines to be moisture sensitive. During wet weather we recommend that imported structural fill meet the requirements of Gravel Borrow as specified in Section 9-03.14(1) of the WSDOT Standard Specifications. Retaining WO Backfili: With the exception of permanent foundation walls constructed directly in front of soldier pile retaining walls, any site retaining walls should include a drainage fill zone extending at least two feet back from the back face of wall for the entire wall height. The drainage fill should meet the requirements of Gravel Backfill for Walls as specified in Section 9-03.12(2) of the WSDOT Standard Specifications. Page 11 ZippenrGeo Gct�pr�fessian� CnriEwlt3nts Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 Pavement Subgrades: Any structural fill used within the upper 2 feet below pavement sections should have a minimum California Bearing Ratio (CBR) of 15 when compacted to a minimum of 95 percent of the modified Proctor maximum dry density. A CBR value of 15 is representative of the existing soils encountered when compacted as recommended in this report. Moisture Content: The suitability of soil for use as structural fill will depend on the time of year, the moisture content of the soil, and the fines content (that portion passing the U.S. No. 200 sieve) of the soil. As the amount of fines increases, the soil becomes increasingly sensitive to small changes in moisture content. Soils containing more than about 5 percent fines (such as most of the on -site soils) cannot be consistently compacted to the appropriate levels when the moisture content is more than approximately 2 percent above or below the optimum moisture content (per ASTM D1557). Optimum moisture content is that moisture content which results in the greatest compacted dry density with a specified compactive effort. Fill Placement: Structural fill should be placed in horizontal lifts not exceeding 10 inches in loose thickness. Each lift of fill should be compacted using compaction equipment suitable for the soil type and lift thickness. Each lift of fill should be compacted to the minimum levels recommended below based on the maximum laboratory dry density as determined by the ASTM D1557 Modified Proctor Compaction Test. Moisture content of fill at the time of placement should be within plus or minus 2 percent of optimum moisture content for compaction as determined by the ASTM D1557 test method. Compaction Criteria: Our recommendations for soil compaction are summarized in the following table. Structural fill for roadways and utility trenches in municipal rights -of -way should be placed and compacted in accordance with City of Edmonds codes and standards. We recommend that a geotechnical engineer be present during grading so that an adequate number of density tests may be conducted as structural fill placement occurs. In this way, the adequacy of the earthwork may be evaluated as it proceeds. Page 12 ! ]� Geo�r SrGeo W%utani{ Cansu:'=�nt�, Utility Trenching and Backfilling Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 We recommend that utility trenching conform to all applicable federal, state, and local regulations, such as OSHA and WISHA, for open excavations. Trench excavation safety guidelines are presented in WAC Chapter 296-155 and WISHA RCW Chapter 49.17. Dewatering: Some excavations for utilities and underground structures may encounter zones of perched groundwater or the water table. At the time of our evaluation, slight perched groundwater seepage was encountered in boring B-1/MW-1 at a depth of about 3 feet and in test pits TP-1A and TP1 B at a depth of about 4 feet below grade. Groundwater seepage was encountered below the perched zones in all nine borings at the time of drilling and in subsequent groundwater monitoring well readings. Groundwater depth readings ranged from about 13 to 18 feet below existing grade, or from about elevation 26'/z feet to 23'/z feet at the time this report was prepared. Groundwater seepage rates were generally slight to moderate on those portions of the glacial till located below the water table, and rapid within the underlying glacial advance outwash deposits. The amount of seepage that may be encountered in site excavations will likely be a function of the time of year, the size of the excavation, the excavation depth, and how long the excavation remains open. The type and extent of dewatering measures needed, if any, will be a function of the groundwater conditions at the time of construction. Temporary systems could include pumped sumps, wellpoints or pumped wells. If seepage is encountered, flattening excavation sidewalls may be necessary to reduce the risk of caving. Otherwise, some caving of utility trench sidewalls should be anticipated where groundwater seepage is encountered. If dewatering becomes necessary, the appropriate type of dewatering system and means of disposing the water should be determined by the contractor based on the conditions encountered. Utility Subgrade Preparation: We recommend that all utility subgrades be firm and unyielding and free of all soils that are loose, disturbed, or pumping. Such soils should be removed and replaced, if necessary. All structural fill used to replace over -excavated soils should be compacted as recommended in the Structural Fill section of this report. If utility foundation soils are soft, we recommend that they be over -excavated 12 inches and replaced with crushed rock. Structures such as manholes and catch basins which extend into soft soils should be underlain by at least 12 inches of crushed gravel fill compacted to at least 90 percent of the modified Proctor maximum dry density. This granular material could consist of crushed rock, quarry spalls, or coarse crushed concrete. Alternatively, quarry spalls or pea gravel could be used until above the water level. It may be necessary to place a geotextile fabric over the native subgrade soils if they are too soft, to provide a separation between the bedding and subgrade soils. Bedding: We recommend that a minimum of 4 inches of bedding material be placed above and below all utilities or in general accordance with the utility manufacturer's recommendations and local ordinances. We recommend that pipe bedding consist of Gravel Backfill for Pipe Zone Page 13 Mar-Vel Marble Redevelopment ,SrZippo Project No. 1798.01 enprofmtonalconglltzlnt4 November21, 2017 Bedding as specified in Section 9-03.12(3) of the WSDOT Standard Specifications. All trenches should be wide enough to allow for compaction around the haunches of the pipe, or material such as pea gravel should be used below the spring line of the pipes to eliminate the need for mechanical compaction in this portion of the trenches. If water is encountered in the excavations, it should be removed prior to fill placement. Trench Backfill: Materials, placement and compaction of utility trench backfill should be in accordance with the recommendations presented in the Structural Fill section of this report. In our opinion, the initial lift thickness should not exceed one foot unless recommended by the manufacturer to protect utilities from damage by compacting equipment. Light, hand operated compaction equipment may be utilized directly above utilities if damage resulting from heavier compaction equipment is of concern. Temporary and Permanent Slopes We anticipate that temporary open cuts may be utilized in conjunction with shoring during the construction of foundation elements for the proposed structure. Temporary excavation slope stability is a function of many factors, including: ■ The presence and abundance of groundwater; • The type and density of the various soil strata; • The depth of cut; • Surcharge loadings adjacent to the excavation; and • The length of time the excavation remains open. As the cut is deepened, or as the length of time an excavation is open increases, the likelihood of sidewall sloughing or failure increases; therefore, maintenance of safe slopes and worker safety should remain the responsibility of the contractor, who is present at the site, able to observe changes in the soil conditions, and monitor the performance of the excavation. It is exceedingly difficult under the variable circumstances to pre -establish a safe and "maintenance -free" temporary cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe temporary slope configurations since the contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. Unsupported vertical slopes or cuts deeper than 4 feet are not recommended if worker access is necessary. The cuts should be adequately sloped, shored, or supported to prevent injury to personnel from local sloughing and spalling. Temporary slope angles should conform to applicable Federal, State, and Local regulations based on the subsurface conditions observed at the time of construction. Based on the conditions observed in the borings and test pits, the weathered glacial till soils encountered in the upper 4 to 10 feet of the explorations appear to be representative of Type B soils, as described in Chapter 296-155, Part N, Excavation Trenching and Shoring, of the Page 14 Mar-Vel Marble Redevelopment � S rG eo Project No. 1798.01 recur 6asionai �ansui x=.nts November 21, 2017 Washington Administrative Code (WAC). According to the Code, excavations less than 20 feet deep in Type B soils may be cut at a maximum temporary slope angle of 45 degrees (1H:1V). The underlying unweathered glacial till soils encountered in the explorations appear to be representative of Type A soils, as described in Chapter 296-155, Part N, Excavation Trenching and Shoring, of the Washington Administrative Code (WAC). According to the Code, excavations less than 20 feet deep in Type A soils may be cut at a maximum temporary slope angle of 53 degrees (3/4H:1V). Therefore, for preliminary planning purposes we recommend maximum temporary slope angles of 45 degrees (1H:1V) and 53 degrees (3/4H:1V) for weathered and unweathered glacial till soils, respectively. According to Chapter 296-155 of the WAC, the contractor should make a determination of excavation side slopes based on classification of soils and site conditions encountered at the time of excavation. Temporary cuts may need to be constructed at flatter angles based upon the soil moisture and groundwater conditions at the time of construction and the location of soil stockpiles construction equipment, or other surcharge loads. Adjustments to the slope angles should be determined by the contractor at that time. We recommend that all permanent cut or fill slopes constructed in native soils be designed at a 2'/2H:1 V (Horizontal:Vertical) inclination or flatter. All permanent cut and fill slopes should be adequately protected from erosion both temporarily and permanently. Temporary Soldier Pile Shoring We understand that the new development will have roughly the same footprint as the existing structures (about a 1-foot lot -line setback with a few portions of the building set back about 3 to 4 feet). Preliminary plans indicate that the below grade parking level will have finished floor elevations ranging from about 32.7 to 31 feet. These parking level finished floor elevations are about 5 to 11 feet below existing exterior grades and we anticipate that excavations for foundation elements may extend about 1'h to 2 feet deeper for anticipated construction excavation depths of 7 to 13 feet. The eastern 25 feet of the building includes a below grade utility room with a finished floor elevation of 37 feet and a 5-foot diameter stormwater detention pipe with an invert elevation of about 30 feet. The utility room finished floor elevations is about 5 to 7 feet below existing exterior grades and we anticipate that excavations for foundation elements may extend about 1'/z to 2 feet deeper for anticipated construction excavation depths of 7 to 9 feet with deeper excavations for the stormwater detention pipe. Based on the preliminary plans, we anticipate that temporary shoring will be needed along the perimeter of the site. Temporary construction easements for excavations and or shoring within the City of Edmonds right-of-way may also be needed depending on the layout and design of the shoring system. Temporary Soldier Pile Sh )ring Considerations: Soldier pile walls consist of vertical steel beams installed in drilled shafts that extend below the bottom of the cut. The shafts are typically backfilled below the bottom of the cut with structural or lean -mix concrete and controlled density fill (CDF) above the bottom of the cut. Once the cementitious material has hardened, the excavation Page 15 %% • r Mar-Vel Marble Redevelopment LI pp��0 Project No. 1798.01 reo�r. fessiai„ t Comtilmnts November 21, 2017 proceeds and lagging (typically dimensional lumber for temporary applications) is installed between the flanges of the vertical elements to support the cut as the excavation extends down. Soldier pile and lagging walls that are not exposed to significant surcharge loads can typically cantilever to a maximum exposed height of about 15 feet. Beyond these heights, or if surcharge loads are sufficient, tie back anchors are typically required to provide additional lateral support. The length of tie backs is typically on the order of 25 to 50 feet, depending on the required anchor capacities. Provided the maximum exposed height of temporary shoring on this project is about 15 feet or less, we expect cantilever -type soldier pile shoring will be feasible for this project. Rapid groundwater seepage rates were observed within the glacial advance outwash deposits encountered about 24 to 30 feet below existing grade, and heave was noted within this unit in some of the borings. To reduce the potential for soldier pile wall shaft instability during construction, we recommend that the design soldier pile shaft excavation depth be maintained at least 3 feet above the glacial advance outwash deposits, if feasible. During our evaluation for this project, ZGA representatives monitored the excavation of two soldier pile drilled shafts completed on the property to the east of the subject site and interviewed the foreman for the shoring contractor, Pile Contractors, Inc. At that site, significant water intrusion into the shaft excavations typically occurred at depths of about 20 to 22 feet. The contractor indicated that they could maintain borehole stability using a synthetic drilling fluid additive without the need for temporary casing, and placed shaft concrete using tremie methods. We recommend that the contractor for this project be prepared to case shafts or use other means to stabilize shaft excavation, as needed. We further recommend that the shoring contractor's bid include a line item for borehole stabilization and that the project schedule include provisions for stabilization measures, if needed. Please refer to the Utility Trench and Backfilling section of this report for a discussion regarding construction dewatering. The shoring design criteria presented in this report should be used by the shoring designer to design an appropriate shoring system. The shoring design should be reviewed by Zipper Geo Associates for conformance with design criteria presented herein. It is generally not the purpose of this report to provide specific criteria for construction methods, materials or procedures for shoring. It should be the responsibility of the shoring designer and contractor to verify the subsurface conditions prior to bidding and determine select appropriate materials and methods for design and construction. Soldier Pile Shoring and Lagging Desicln Parameters: The design of shoring is generally accomplished using empirical relationships and apparent earth pressure distributions. These earth pressure distributions or envelopes do not represent the precise distribution of earth pressures but rather constitute hypothetical pressures from which tieback loads can be calculated which would not likely be exceeded in the excavation. Additionally, pressures must be selected to limit deflections, both vertical and horizontal, of nearby settlement sensitive structures, roadways and utilities. The design of soldier pile and lagging shoring should include lateral pressures exerted by the adjacent soil, surcharge loads from the adjacent building, and other surcharges such as traffic, construction materials, crane pad loads, or temporary soil stockpiles Page 16 �i�per�eo Mar-Vel Marble Redevelopment Project No. 1798.01 sac W feSannal Consultants November 21, 2017 adjacent to the excavation. 'Lateral load resistance can be mobilized passive pressures on members that extend below the bottom of the excavation. Increased lateral load resistance could be mobilized through the use of tiebacks that extend beyond the pressure envelopes, if needed. Design of soldier pile shoring should be based on either "active" or "at -rest" lateral earth pressures, depending on the degree of deformation that the shoring wall can tolerate. Lateral wall movement for soldier pile shoring designed using active earth pressures typically range from about 0.2 percent to 0.5 percent of the wall height. The lateral movement is typically accompanied by vertical settlement of about 0.15 percent to 0.5 percent of the wall height with the maximum occurring immediately behind the wall face and trending to zero at a distance of roughly two times the wall height. If existing utilities or buildings within the zone of influence are considered to be insensitive to this degree of settlement, then it would be appropriate to design utilizing active earth pressures. An assumed "at -rest" earth pressure condition theoretically assumes no movement of the soil behind the shoring, however, some settlement should realistically be anticipated due to construction practices and/or the fact that it is not possible to construct a perfectly stiff shoring system. The attached Temporary Soldier Pile Shoring Design Parameters, Figure 4 provides our recommendations for cantilever soldier pile shoring design. Additionally, construction loads such a stockpiled soils and crane outrigger loads must be applied. Figure 5 provides pressure diagrams for lateral earth pressures resulting from vertical surcharges behind shoring walls. For traffic surcharges on the shoring walls we recommend using an equivalent soil surcharge of 2 feet (250 psf) be added to the walls extending down to an elevation based on a 1H:1V influence line from the drive surface to the shoring. Construction of soldier pile shoring walls should be in accordance with Section 6-16 of the WSDOT Standard Specifications. When caving soil conditions are encountered in soldier pile excavations, we recommend the contractor case or otherwise stabilize the excavation in general accordance with WSDOT Standard Specification Section 6-16.3(3), Shaft Excavation. We anticipate that the saturated glacial advance outwash deposits encountered at depths of about 24 to 30 feet below grade in our explorations will be highly susceptible to caving. We also recommend that shaft backfilling be completed in general accordance with WSDOT Standard Specification Section 6-16.3(5), Backfilling Shaft, particularly with respect to when water is present in the excavations. We recommend the contractor be prepared to clean out the bottom of all shafts using a clean -out bucket so that slough is limited to 2 inches or less. Shoring Monitoring Plan: Any time an excavation is made below the level of existing buildings, utilities or other structures, there is risk of damage even if a well -designed shoring system has been planned. If there are settlement -sensitive structures or facilities located within a horizontal distance of two times the wall height, we recommend a shoring monitoring program be implemented. Page 17 Mar-Vel Marble Redevelopment � � rG- eo Project No. 1798.01 uecpr�)`essiona! Carstdt=Ints November 21, 2017 In order to establish the condition of existing facilities prior to construction, we recommend that the owner and/or representatives make a complete inspection and evaluation of pavements, structures, and utilities around the proposed excavation. This inspection should be directed towards detecting any existing signs of damage, particularly those caused by settlement or lateral movement. The observations should be documented by pictures, notes, survey drawings, or other means of verification. The contractors also should establish for their own records the existing conditions prior to construction. The monitoring program should include measurements of the horizontal and vertical movements of the adjacent structures and the shoring system itself. At least two reference lines should be established adjacent to the excavation at horizontal distances back from the excavation space of about 1/4H and 3/4H, where H is the final excavation height. Reference points for horizontal movement should also be placed at the tops of the soldier piles. The measuring system used for shoring monitoring should have an accuracy of at least 0.01-foot. All reference points on the existing structures should be installed and readings taken prior to commencing the excavation. All reference points should be read prior to and during critical stages of construction when the piles are not braced by the structure. The frequency of readings will depend on the results of previous readings and the rate of construction. As a minimum, readings should be taken at least once a week throughout construction until the permanent basement walls are completed up to the ground level of the building. All readings should be reviewed by the geotechnical and structural engineers. Shallow Foundations Based on our analyses, conventional spread footings will provide adequate support for the proposed building provided that the foundation subgrades are properly prepared. Foundation support for the building may be obtained from either the native glacial till deposits or from new structural fill placed in accordance with the recommendations provided in this report. The upper one foot of foundation subgrades should be moisture conditioned, as necessary, and compacted to a firm and non -yielding condition and to at least 95 percent of the modified Proctor maximum dry density per ASTM D 1557. Borings B-1/MW-1, B-2/MW-2. B-8/MW-8, and test pits TP-2A and B encountered up to about 5'/z feet of existing fill. We do not recommend supporting foundations on existing fill soils. If unsatisfactory fills are encountered within the proposed building area, such fills should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. For all footings, we recommend that any over -excavation of unsuitable fill soils extend outside the limits of the footings a distance equal to the depth of over -excavation, with the exception of footings constructed against shoring walls in which case the over excavation along the face of the shoring wall may be vertical. Foundation design recommendations are presented in the following sections. Page 18 Mar-Vel Marble Redevelopment Z [ i`" p rG e Q Project No. 1798.01 Gec{sr e'ss�nn, i'_r,:.<„+:ants November 21, 2017 Allowable Bearing Pressure: Continuous and isolated column footings bearing on subgrades prepared as recommended above may be designed for a maximum allowable, net, bearing pressure of 3,000 psf if supported on compacted structural fill or native medium dense silty sand deposits, and 4,500 psf if supported on dense to very dense, undisturbed, silty sand deposits. A one-third increase of the bearing pressure may be used for short -tern dynamic loads such as wind and seismic forces. Shallow Foundation Depth and Width: For frost protection, the bottom of all exterior footings should bear at least 18 inches below the lowest adjacent outside grade, whereas the bottoms of interior footings should bear at least 12 inches below the surrounding slab surface level. We recommend that all continuous wall and isolated column footings be at least 12 and 24 inches wide, respectively. Lateral Resistance: We recommend using allowable base friction and passive earth values of 0.35 and 325 pcf equivalent fluid pressure, respectively. We recommend that passive resistance be neglected in the upper 18 inches of embedment. Estimated Settlement: Assuming the foundation subgrade soils are prepared in accordance with recommendations presented herein, we estimate that total and differential settlements will be less than one inch and '/z inch, respectively, over a distance of 40 feet. Permanent Retaining Walls We expect the project to include some backfilled cast -in -place concrete retaining walls. For recommended bearing capacities and lateral resistance parameters, refer to the Shallow Foundations section above. Additional recommendations for these structures are provided below. Lateral Earth Pressures: The lateral soil pressures acting on backfilled retaining walls will depend on the nature and density of the soil behind the wall, and the ability of the wall to yield in response to the earth loads. Yielding walls (i.e. walls that are free to translate or rotate) that are able to displace laterally at least 0.001 H, where H is the height of the wall, may be designed for active earth pressures. Non -yielding walls (i.e. walls that are not free to translate or rotate) should be designed for at -rest earth pressures. Non -yielding walls include walls that are braced to another wall or structure, and wall corners. Assuming that walls are backfilled and drained as described in the following paragraphs, we recommend that yielding walls supporting horizontal backfill be designed using an equivalent fluid density of 34 pcf (active earth pressure). Non -yielding walls should be designed using an equivalent fluid density of 55 pcf (at -rest earth pressure). Design of permanent retaining walls should consider additional earth pressure resulting from the design seismic event. For the seismic case, walls should be designed for an additional uniform, total seismic earth pressure distribution of 11 H. Page 19 ZIpp�r� Mar-Vel Marble Redevelopment Project No. 1798.01 Greprv`:ssianaf Con5u3 MUS November 21, 2017 The above -recommended lateral earth pressures do not include the effects of sloping backfill surfaces, surcharges such as traffic loads, other surface loading, or hydrostatic pressures. Traffic surcharge loads on the basement walls can be evaluated considering an equivalent soil surcharge of 2 feet (250 psf) added to the walls extending down to an elevation based on a 1 HA V influence line from the drive surface to the wall, similar to the methodology recommended for the shoring walls. If other surcharge conditions exist, we should be consulted to provide revised earth pressure recommendations. Slab -on -Grade Floors Based on preliminary plans, it appears that the utility room located in the eastern portion of the building will include a conventional concrete slab -on -grade floor, while the below grade parking area in the central and western portions of the building will include concrete pavements intended to support passenger vehicle traffic. Recommendations for building slab -on -grade concrete floors and parking garage concrete pavements are presented below. Subgrade Conditions and Pre aration: The native glacial till soils appear to be suitable for support of the slabs provided they can be compacted to the minimum recommended levels. Where unsuitable soil is present, such as loose soils or undocumented fill, we recommend that the material be over -excavated and replaced with common borrow or select borrow, depending on the prevailing weather conditions. Subgrades should be prepared in accordance with the recommendations presented in the Subgrade Preparation section of this report. Slab Base: To provide a uniform slab bearing surface, we recommend the on -grade slabs in non - parking areas be underlain by a 4-inch thick layer of compacted crushed rock meet the requirements of Crushed Surfacing Top Course as specified in Section 9-03.9(3) of the WSDOT Standard Specifications. Within the parking garage, we recommend that the top course thickness be increased to 6 inches. Vapor Retarder: From a geotechnical standpoint, a vapor barrier is not considered to be necessary for the proposed building. Where potential slab moisture is a concern or where moisture sensitive floor coverings are planned, we recommend that a 10- to 15-mil moisture barrier be installed beneath all interior slabs. We recommend using a puncture -resistant product such as Stego Wrap or an approved equivalent that is classified as a Class A vapor retarder in accordance with ASTM E1745. Puncturing the vapor barrier should be avoided; construction traffic should not be allowed to drive over any vapor barrier material. The slab designer should and contractor should refer to ACI 302 for procedures and cautions regarding the use and placement of a vapor retarder. We recommend that installation of the vapor barrier be completed in accordance with the manufacturers recommendations. ZGA is completing Phase II environmental services to evaluate the approximate extent and concentration of contaminants that may be present on site. If soil or groundwater containing Page 20 Z i p pe r o Mar-Vel Marble Redevelopment Project No. 1798.01 Geapro!'�slnnaICon$LtITant` November 21, 2017 volatile organic compounds (VOCs) are encountered below planned excavation depths a more extensive vapor retarder system than recommended above may be warranted and recommended in our Phase II report to reduce the potential for vapor intrusion into the building. Sub_ rade Modulus: For design of on -grade concrete slabs supported on dense to very dense native soils, we recommend a vertical modulus of subgrade reaction of 250 pounds per cubic inch (pci) be used. For slabs supported on compacted structural fill or medium dense native soil, we recommend using a vertical modulus of subgrade reaction of 200 pounds per cubic inch. Parking Garage Concrete Pavement: The following parking level concrete pavement design recommendations are based on an assumed modulus of rupture of 600 psi and a minimum compressive strength of 4,000 psi for the concrete. For light duty pavement, we recommend a minimum of 5 inches of concrete over 6 inches of crushed aggregate base. Based on the soils encountered, we recommend that concrete pavements be lightly reinforced to control cracking and have relatively closely spaced control joints on the order of 10 to 12 feet. We recommend that minimum reinforcement consist of 6x6-W2.OxW2.0 welded wire fabric, or equivalent. Drainage Considerations Surface Drainage: Final site grades should be sloped to carry surface water away from buildings and other drainage -sensitive areas. Additionally, site grades should be designed such that concentrated runoff on softscape surfaces is avoided. Sub -slab Drainage: Due to the low permeability of the glacial till soils beneath the garage slab, and observed groundwater conditions, we recommend that sub -slab drains be installed below the parking level concrete slab -on -grade floor. We recommend using 4-inch diameter perforated PVC pipes embedded at least 2 feet below the bottom of the slab that are spaced on 15- to 20-foot centers. We recommend that the trenches be backfilled with aggregate meeting the gradation requirements of WSDOT Standard specification 9-03.12(4), Gravel Backfill for Drains and that the trenches be lined with a non -woven filter fabric such as Mirafi 140N or equivalent prior to placing the drainpipe and drainage aggregate. We recommend the pipes have a minimum slope of 6 inches in 50 feet. The pipes should be laid out such that they do not interfere with the bearing soils of adjacent foundations. Bearing soils within an envelope defined by extending horizontally one foot from all sides of a foundations and then down at a 1 H:1V slope should not be disturbed. Subsurface Perimeter Drainage: We recommend a permanent subsurface drainage system be installed around the perimeter of the structure. We anticipate two types of systems may be required; a system for backfilled retaining walls and a system for walls cast against temporary shoring walls. Our recommendations for each are provided below. Backfilled Walls: Drains for backfilled walls should consist of an aggregate drainage zone (as recommended in the Structural Fill section) and a drain pipe. The footing drains should consist of a minimum 4-inch diameter, Schedule 40, rigid, perforated PVC pipe placed at Page 21 Zip p�rGeo Geaprale:W0naILnr.: -=rants Mar-Vel Marble Redevelopment Project No. 1798.01 November 21, 2017 the base of the heel of the footing with the perforations facing down. The pipe should be surrounded by a minimum of 6 inches of clean free -draining granular material conforming to WSDOT Standard Specification 9-03.12(4), Gravel Backfill for Drains. A non -woven filter fabric such as Mirafi 140N, or equivalent, should envelope the free -draining granular material. At appropriate intervals such that water backup does not occur, the drainpipe should be connected to a tightline system leading to a suitable discharge. Cleanouts should be provided for future maintenance. The tightline system must be separate from the roof drain system. Walls Cast Against Shoring Walls: Prefabricated drainage matting (such as Miradrain or J-Drain 400) should be placed on the outside face of shoring (lagging) full width and height of the wall between soldier pile flanges. Near the bottom of the wall, and at the center between soldier piles, a prefabricated connector (such as Drain Grate) should be connected to the drainage matting. The connector should be fitted with a 3-inch minimum diameter weep hole pipe that will extend through the face of the permanent foundation wall. The weep hole pipe should be connected to a tightline system leading to a suitable discharge. CLOSURE The analysis and recommendations presented in this report are based, in part, on the explorations completed for this study. The number, location, and depth of the explorations were completed within the constraints of budget and site access so as to yield the information to formulate our recommendations. Project plans were in the preliminary stage at the time this report was prepared. We therefore recommend we be provided an opportunity to review the final plans and specifications when they become available in order to assess that the recommendations and design considerations presented in this report have been properly interpreted and implemented into the project design. The performance of earthwork, structural fill, shoring, foundations, and pavements depend greatly on proper site preparation and construction procedures. We recommend that Zipper Geo Associates, LLC be retained to provide geotechnical engineering services during the earthwork - related construction phases of the project. If variations in subsurface conditions are observed at that time, a qualified geotechnical engineer could provide additional geotechnical recommendations to the contractor and design team in a timely manner as the project construction progresses. This report has been prepared for the exclusive use of Mary Olsen, and her agents, for specific application to this project and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Zipper Geo Associates, LLC reviews the changes and either verifies or modifies the conclusions of this report in writing. Page 22 REFERENCE: GOOGLE EARTH 2O17 VICINITY MAP NOT TO SCALE SITE AND EXPLORATION PLAN LEGEND: FIGURE 2 �B-1/MW-1 BORINGIGROUNDWATER MONITORING WELL NUMBER AND APPROXIMATE LOCATION ',M TP-1A TEST PIT NUMBER AND APPROXIMATE LOCATION A A' GENERALIZED SUBSURFACE PROFILE APPROXIMATE LOCATION AND DESIGNATION GENERALIZED CROSS SECTION LEGEND : FIGURE 3 B-11MW-1 (OFFSET 15' W) EXPLORATION NUMBER - BORING OFFSET DISTANCE & DIRECTION FROM SECTION LINE GROUND WATER LEVEL WHILE DRILLING OR DATE NOTED GROUNDWATER MONITORING WELL SAND PACK 32 STANDARD PENETRATION TEST (SPT) BLOWCOUNT ? ? - APPROXIMATE SOIL UNIT BOUNDARY (INTERPOLATED BETWEEN EXPLORATIONS) TD=35.5 TOTAL DEPTH OF EXPLORATION IN FEET GENERAL NOTES FOR FIGURES 2 AND 3 1. THE TOPOGRAPH3C AND BUILDING LAYOUT BASE MAPS PRESENTED ON FIGURE 2 ARE TAKEN FROM THE PRELIMINARY GRADING AND UTILITY PLAN, SHEET C3.1, PREPARED BY GC ENGINEERING, DATED OCTOBER 6, 2016. 2. THE LOCATION AND ELEVATION OF THE BORINGS SHOWN ON FIGURES 2 AND 3 WERE PROVIDED BY PACIFIC COAST SURVEYS, INC. THE LOCATION AND ELEVATION OF THE TEST PITS ARE BASED ON FIELD MEASUREMENTS TAKEN WITH A FIBERGLASS TAPE MEASURE RELATIVE TO EXISTING SITE FEATURES VISIBLE ON THE ABOVE REFERENCED BASE MAP, AND SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE MEASUREMENT METHODS. 3. THE SUBSURFACE CONDITIONS SHOWN ON THE GENERALIZED CROSS SECTION ARE BASED UPON INTERPOLATION BETWEEN EXPLORATIONS AND MAY NOT REPRESENT ACTUAL SUBSURFACE CONDITIONS. SIMPLIFIED NAMES ARE SHOWN FOR SOIL DEPOSITS, BASED ON GENERAIIYATIONS OF SOIL DESCRIPTIONS. SEE EXPLORATION LOGS AND REPORT TEXT FOR MORE DETAILED SOIL AND GROUNDWATER DESCRIPTIONS. 1<y{S[pAEh t � UP§RAaS 4"Ti aRAMP - - I _•'N Fpt C[rf R[aIAAN.IIM1IL , - �' I � WI rRU]fG�P�aMf/S . Sk <nnE�ranat ry 'Cii 8 21MW-2 ~I~~ Q ^? �crt t B-71MW-7UFO 'm +: f I i m�sE► - •• it I -A'RS4�HF�y,�-•r ■ ��iTarlQ+ltlC 1 ! wsukn9E fl�&�HHH TP-1B - - TP-1A eRx�r,n II I IiI UP'PADINDEW'AM 44 13-81MW-8 ' .{�' kfJJR4ST0 ClTV L TP-4 Y A. .. P AU0*6 YHa[RHYCUHO ►aWE~R Eu•ru[etsoeo 4-94'ST,METrIKEE _ \ . -•. j ti�� maxi TP-2A R / J B-61MW-6 7MRY fitfi l4 r VfAl1 PER Alll7i PpCTa#: miNe B-4/MW-4l9I / I � IE 39,St I h I TP-3^ssa xMN 4 ' B-5/MW-5 ® I � 14 I _ - I T 39.a �SFL 7!• PCAI I. :� � � � I. ••1 B-S1MW9[uArla[li .. B•3IMW _� � .If•J �. • I � REQ4ARFa IN:VrVHE �.. �".' .:�• � ° � ` �I+ASES OFaiSRSN B-11MW-1: W/YTPEkI h, BUILDING LAYOUT AND GRADING REFERENCE: PRELIMINARY GRADING AND UTILITY PLAN, SHEET C3.1, PREPARED BY CG ENGINEERING, DATED OCTOBER 6, 2016. FT6 SSE? tvAUES TYR! i lE -' SalaM IEE OETEN'IaN SYSTEM • SaA 'Fa AU¢LC 51aAM T"E31C9wfFmw S1 nmi-m CaNTR.a MucrURE aonAilE 1'1" IE ltr M-Z-1 BASEMENT PLAN N 3a 0 19 >0 SCALEIN FEET SITE AND EXPLORATION PLAN FIGURE SHT1 oft A 60 50 40 F- ? ------- LLI ? ------- w ? -- �-- LL. 30 ?------- Z z 5- 0 6- 20 J? ------- LLI 10 -10 0 (OFFSET 23' SE) (OFFSET 58' SE) B-4 (OFFSET 58' SE) B-2 (OFFSET 45' NW) — SILTY SAND, SOME SILTY SAND, SOME GRAVEL GRAVEL (FILL) (WEATHERED GLACIAL TILL) SAND, TRACE TO SOME SILTY SAND, SOME SILT (GLACIAL OUTWASH) j I GRAVEL (FILL) I GROU 27 _._� - - '` 30 - - -----_ `�-------------' 57 --- 32 33 57 65 FFE 31 FEET - 67 ANTICIPATED CUT DEPTH 37 -17 40 30 SILTY SAND, SOME 54 -_--- -- .---- ----.•- - - - - 36 5-22-17 6.7-17 9,14-17 GRAVEL (GLACIAL TILL) H447---- -_-. " SAND, WITH SILT & wo 17 50/5" H° 50/3" --- __ -- - - - _--?----" �° 59 GRAVEL (GLACIAL TILL) 50/6" -- 50/6" 79 -------- 5016" ----•-------- wa 50/6" 50/3" �{ - 58 - 37 SAND, TRACE TO SOME SAND, SOME SILT 56 SILT, TRACE GRAVEL %_ 51 (GLACIAL ADVANCE TD=35' TD=36.5' (GLACIAL ADVANCE TD=36.5' OUTWASH) TD=35' OUTWASH) 10 20 30 40 50 60 70 80 90 DISTANCE IN FEET r 60 50 40 W w 1 LL. 30 Z ---------- ? - O ~ 20 ---?-----= W ---?---? W 10 11 I 1 -10 100 110 120 130 140 MARVEL MARBLE REDEVELOPMENT 202 Man Street Edmonds, Waslington GENERALIZED CROSS SECTION A -A' DA r2017 Mbmn 11901 71ppor Geo As oclate , LLC I FIGURE e� 19019 36th Ave- W.,Wte E 3 Lvnnwood. WA SHL1 oft TOP OF IIV FINISHE4ER BOTTOM OF Pa DEPTH TO GROUNDWAVARIABLE BASEDGROUNDWATER BOTTOM OF EXCAVAELEVATION FOR SHORING ELEVADESIGN: 26 FEET ' It �• •' �I 1. i[ • ;Ir, •FE Il �� m Pl l . . •11 Pa Dl' q Z (8' MIN.) ll JI. 11' '• l i 11 _ll PASSIVE f ACTIVE PRESSURE D ---4— PRESSURE CANTILEVER PRESSURE DIAGRAM SOLIDER PILE SHORING DESIGN PARAMETERS ACTIVE EARTH ACTIVE EARTH ULTIMATE PASSIVE ULTIMATE PASSIVE PRESSURE PRESSURE ULTIMATE ULTIMATE PRESSURE ABOVE PRESSURE BELOW BACKSLOPE GROUNDWATER GROUNDWATER RESISTENCE ABOVE RESISTANCE BELOW SKIN FRICTION, END BEARING, TABLE, GROUNDWATER TABLE, GROUNDWATER GROUNDWATER GROUNDWATER (tso (tso TABLE, Pp (pc� TABLE, Pp (pc> LEVEL 34 17 600 325 0.30 15 1.5H:1V 62 32 600 325 j 0.30 15 NOTES: 1. ALL DIMENSIONS IN FEET. 2. PASSIVE LATERAL EARTH PRESSURE PRESENTED HEREIN ARE ULTIMATE, AN APPROPRIATE SAFETY FACTOR SHOULD BE APPLIED. 3. PASSIVE PRESSURE APPLY OVER TWO CONCRETED PILE DIAMETERS OR PILE SPACING, WHICHEVER IS LESS. 4. ACTIVE PRESSURE APPLIES OVER PILE SPACING ABOVE EXCAVATION BASE AND OVER ONE PILE DIAMETER BELOW EXCAVATION BASE. &SHORING DESIGN MUST SATISFY FORCE AND MOMENT EQUILIBRIUM ANALYSES. 6. SEE REPORT TEXT AND FIGURE 5 FOR CALCULATION OF SURCHARGE LOADS ACTING ON THE WALL, AND FOR ADDITIONAL RECOMMENDATIONS, 7. FOR TRAFFIC SURCHARGES, USE 2 -FOOT EQUIVALENT SOIL SURCHARGE POINT LOAD x=mD (FOR m > 0.4) 1.77q rn2 n 2 � D 6h = D 2 - (rn2+ n2 )3 D (FOR m 5 0.4) Gh 0.28q n 2 6h _D 2 - (0.16 + n2)3 BASE OF EXCAVATION L2 rlq, b per ft2 LINE LOAD PRESSURE x=mD z=nD D CUT q, lb per ft2 6h BASE OF EXCAVATION 6'h =6h cost (1.1*0) k)q Uh h f O f PLAN VIEW OF WALL O in degrees STRIP LOADING PARALLEL TO EXCAVATION 6h = 2�q (p- sin (iCOS 2a) a and R in radians LINE LOAD (FOR m > 0.4) 1.28q m 2 n 6h - D ' (m2+ n2)2 (FOR m <_ 0.4) _ ! q 6h D 0.2n (0.16 + n2 )2 UNIFORM LOAD DISTRIBUTION 6h = (Ka or Ko) q q = Vertical pressure in psf Ka (Active) = Tan'(45 - 0/2) Ko (At Rest) = 1 - Sin O O = 36' BASE OF EXCAVATION APPENDIX A FIELD EXPLORATION PROCEDURES AND LOGS FIELD EXPLORATION PROCEDURES Our field exploration included nine borings and four test pits completed between April and September 2017. The approximate exploration locations are presented on the enclosed Site and Exploration Plan, Figure 2. Boring locations and ground surface elevations were provided to ZGA by Pacific Coast Surveys, Inc. Test pit exploration locations were determined in the field by measuring distances from existing site features with a fiberglass tape relative to a Topographic and Boundary Survey prepared by Geo Dimensions dated April 11, 2016. Ground surface elevations at the test pit locations were interpolated from topographic lines presented on the Topographic and Boundary Survey. The vertical datum is reported as NAVD 88. As such, the exploration locations and elevations should be considered accurate only to the degree implied by the measurement methods. The following sections describe our procedures associated with the explorations. Descriptive logs of the explorations are enclosed in this appendix. Soil Boring Procedures Borings were advanced using hollow -stem auger drilling methods by an independent drilling companies working under subcontract to our firm. Borings B-1/MW-1 and B-1/MW-2 were advanced using a limited -access, track -mounted drill rig operated by Geologic Drill, Inc. Borings B-2/MW-2 through B-9/MW-9 were advanced using a truck -mounted drill rig operated by Environmental Drilling, Inc. A geologist from our firm continuously observed the borings, logged the subsurface conditions encountered, and obtained representative soil samples. All samples were stored in moisture -tight containers and transported to our laboratory for further visual classification and testing. Throughout the drilling operation, soil samples were obtained at 2.5- to 5-foot intervals by means of the Standard Penetration Test (ASTM: D-1586). This testing and sampling procedure consists of driving a standard 2-inch outside diameter steel split spoon sampler 18 inches into the soil with a 140-pound hammer free falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is recorded, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or "blow count" (N value). If a total of 50 blows are struck within any 6-inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the relative consistency of cohesive soils. The enclosed boring logs describe the vertical sequence of soils and materials encountered in each boring, based primarily upon our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, as well as any laboratory tests performed on these soil samples. If groundwater was encountered in a borehole, the approximate groundwater depth, and date of observation, is depicted on the log. Groundwater monitoring wells were installed in both explorations completed for this project. Monitoring well construction details are presented on the boring logs. Post exploration groundwater levels measured in the monitoring wells are reported on the boring logs and in the report text. The boring logs presented in this appendix are based upon the drilling action, observation of the samples secured, laboratory test results, and field logs. The various types of soils are indicated as well as the depth where the soils or characteristics of the soils changed. It should be noted that these changes may have been gradual, and if the changes occurred between sample intervals, they were inferred. Test Pit Procedures An independent contractor working under subcontract to the Owner excavated the test pits using a tracked -mounted excavator. A geologist from our firm continuously observed the test pit excavations, logged the subsurface conditions, and obtained representative soil samples. The samples were stored in moisture tight containers and transported to our laboratory for further visual classification and testing. After we logged each test pit, the operator backfilled each test pit with excavated soils tamped into place. Some settlement of the backfill should be expected over time. The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in each test pit, based primarily on our field classifications and supported by our subsequent laboratory testing. Where a soil contact was observed to be gradational or undulating, our logs indicate the average contact depth. We estimated the relative density and consistency of in situ soils by means of the excavation characteristics and by the sidewall stability. Our logs also indicate the approximate depths of any sidewall caving or groundwater seepage observed in the test pits, as well as all sample numbers and sampling locations. See Figure 2, Site and Exploration Plan 40.88 Feet 4/28/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries Q between soil types. The transition may be gradual. Refer to report text and appendices for additional information. 0 6 inches of concrete -- _- ---- Drllllno Compaq Geologic Drill Bore Hole Dia.: 6-Inch Drilling Method: H.S.A. Hammer Type_ Cathead Drill i Rig: Mini -Track Loaned bL JPG L PENETRATION RESISTANCE (blows/foot) 07 E w rcc AL Standard Penetration Test � J m Z n- ° Hammer Weight and Drop: E Q C C 0 20 40 i Loose to medium dense, wet grading to saturated, mottled gray -brown, silty SAND, some gravel (Possible Fill) T (PID < 1 ppm) ----------------_ S-1 I 14" -------n. Medium dense, moist to wet, gray -brown, silty SAND, some o gravel (Weathered Glacial Till) (PID < 1 ppm) 5 Dense, moist to wet, gray, fine to medium SAND, trace to some silt. (Glacial Outwash) (PID < 1 ppm) -------------------------------------- Medium dense, moist, gray -brown, silty SAND, some gravel s-3 16 (Weathered Glacial Till) (PID < 1 ppm) 10 Dense, moist, gray to gray -brown, silty SAND, some gravel T (Weathered Glacial Till) (PID < 1 ppm)--- - -' - -- - - - -�- S_4 I 16^ Very Dense, moist, gray, silty SAND, some gravel (Glacial Till) 1 (PID < 1 ppm) 1� Dense, wet, gray with slight iron oxide staining, silty SAND, some gravel (Glacial Till) (PID < 1 ppm) 20 Very dense, moist, gray to gray -brown, silty SAND, some gravel (Glacial Till) (PID < 1 ppm) 25 SAMPLE LEGE . D I2-inch O.D. split spoon sample 3-inch I.D. Shelby tube sample TESTING ax GSA = Grain Size Analysis 20OW = 200 Wash Analysis Consol. = Consolidation Test Att. = Atterberg Limits GROUNDWATERLEGEND Clean Sand Bentonite Grout/Concrete Screened Casing [� Blank Casing ■ Groundwater level at _ time of drilling (ATD) or r; on date of i measurement. S-5 16" V S-6 1 101, B-11MW-1 I� 27 38 27 1 GSA 72 40 1 GSA 5015" O % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit i G 1 Liquid Limit Natural Water Content Mar-Vel Marble 202 Main Street Edmonds, WA Date: October 2017 Project No.: 1798.01 Zipper Geo Associates BORING B-11MW-1 19019 36th Ave. W. Suite E LOG: Lynnwood, WA Paqe 1 of 2 See Figure 2, Site and Exploration Plan 40.88 Feet 4/28/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries CD between soil types. The transition may be gradual. Refer to ❑ 1 report text and appendices for additional information Drilling Company: Geologic Drill Bore Hole ❑ia.: 6-Inch Drillina Method: H.S.A. Hammer Type, Cathead B-1/MW-1 Drift f2iq_ Mini -Track Loosed by: JPG PENETRATION RESISTANCE (blows/foot) w ` W _ -1 ■ Standard Penetration Test o 0' •- D_ ° Hammer Weight and Drop: V aa) EQ� o o t- U) U) U 0 20 40 60 m 25 Very dense, moist to wet, gray to gray -brown, SAND, with silt s_7 14" and gravel (Glacial Till) (PID < 1 ppm) 30 Very dense, saturated, gray, Fine to medium SAND, trace to s-e 12- some silt, trace gravel (Glacial Advance 0utwash) (PID < 1 ppm) (Moderate to severe heave encountered) 35 Boring completed at about 35 feet. Perched groundwater observed at about 3 feet ATD. Groundwater observed at about 27 feet ATD. Groundwater measured at 14.63 feet on 5122/2017. Groundwater measured at 14.37 feet on 5/26/2017. Groundwater Measured at 14.85 feet on 617/2017. Well Tag # BIK 772 40 45 54 SAMPLE LEGEND G ODUND A i= LEGEND I2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing T Blank Casing GSA = Grain Size Analysis VGroundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis N on date of measurement. Consol. =Consolidation Test Att. = Atterberg Limits min In 05" 50/6" 1 GSA 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit Liquid Limit Natural Water Content Mar-Vel Marble 202 Main Street Edmonds, WA Date: October 2017 Project No.: 1798.01 Zipper Geo Associates 19019 BORING 13-11MWA 36th Ave. W, Suite E Lynnwood, LOG: WA Paae 2 of 2 torinq Lo_ a� See Figure 2, Site and Exploration Plan Drilling ComnanY Geologic Drill Bore Hate Qia.: 6-Inch "ors Elevation: 39.51 Feet Drilling Meths H.S.A. HammerTvQe: Cathead B-2/MW-2 )ate D i E : 4/28/2017 Qril] Rsq Mini -Track Legged by. JPG SOIL DESCRIPTION L PENETRATION RESISTANCE (blows/foot) to E w z / Standard Penetration Test o The stratification lines represent the approximate boundaries J m c Hammer Weight and Drop: U 0 between soil types. The transition maybe gradual. Refer to E Q X � o F- report text and appendices for additional information. n 40 60 m 0 20 0- 4 to 5 inches of concrete - ------------- Medium dense, wet, mottled gray -brown, silty SAND, some IT i gravel (Possible Fill) (Hydrocarbon Odor at Tip of Sampler) ' 1 (PID = 43 ppm) S-1 14" — 3z ----------------------- - - - - -- 11 I�11, Very dense, moist, gray, silty SAND, some gravel (Glacial Till) S-2 I 16„ ' ] J I 65 (Hydrocarbon Odor) (PID = 109 ppm) i I Very dense, moist, gray, silty SAND, some gravel (Glacial Till) S-3 19" i k 67 (Hydrocarbon Odor) (PID = 104 ppm) - I i I I j i 10 Very dense, moist, gray, silty SAND, some gravel (Glacial Till) s_4 T 18„ i i I I IT I 37 (Faint Hydrocarbon odor) (PID = 45 ppm) 1 , cn i _,--- - I i i I 15 Dense, wet to saturated, gray -brown SAND, with silt and 1I TT� S-s T 10� . I V 1 ` 11 36 gravel. (Glacial Till) (PID = 10 ppm) Il< _ I I -� ,20 Very dense, wet to saturated, gray -brown SAND, with silt and 11� S-6 12„ i I I�ii LL I sops GSA gravel (Glacial Till) (PID = 6 ppm) f I I j d25 ----------------- -- ------------------ , Very dense, saturated, gray SAND, some silt (Glacial Advance' I - ! Outwash) (PID = 2 ppm) 1 AMPLE LEGEND GROUNDWAIERIEGENQ 0 % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand %Water (Moisture) Content 3-inch I.D. Shelby tube sample ( Bentonite Plastic Limit Liquid Limit Grout/concrete Natural Water Content Screened Casing Mar-Vel Marble Tt=sil0 Blank Casing 202 Main Street GSA = Grain Size Analysis Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis on date of Date: October 2017 Project No.: 1798.01 ^' Consol. =Consolidation Test measurement. Zipper Geo Associates BORINGB-21MW-2 Att. = Atterberq Limits 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 1 of 2 Boring Location: See Figure 2, Site and Exploration Plan Top Elevation: 39.51 Feet Date Drilled: 4/28/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries Q between soil types. The transition may be gradual. Refer to report text and appendices for additional information. 25 Very dense, saturated, gray SAND, some silt (Glacial Advance Outwash) (PID = 2 ppm) Very dense, wet to saturated, gray, silty SAND, some gravel J (Glacial Till) (PID = 2 ppm) 30 Dense, saturated, gray, fine to medium SAND, trace to some silt (Glacial Advance Outwash) (PID < 1 ppm) 35 Boring completed at about 35 feet. Groundwater observed at about 15 feet ATD. Groundwater measured at 13.18 feet on 5122/2017. Groundwater measured at 13.88 feet on 5/2612017. Groundwater measured at 13.20 feet on 6/7/2017. Groundwater measured at 15.56 feet on 1012/2017. Well Tag # B I K 773 45 50 Drilllnct Company: Geologic Drill Bore Hole Dia.: 6-Inch Drllling Method: H.S.A. Hammer Type: Cathead Drill Rig: Mini -Track Logged by'. JPG PENETRATION RESISTANCE (blows/foot) EJ iu Standard Penetration Test v IL 8Hammer Weight and Drop: �Q o to (7 0 20 40 SAMPLE LEGEND GROUNDWATER LEiaEN� I2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample 01 Bentonite Grout/Concrete Screened Casing TESTING KEY ❑ Blank Casing GSA = Grain Size Analysis Z Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis _ on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits sa B-2/MW c 0) 0 C 0 U u o 60 m 50/6" 37 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit Liquid Limit Natural Water Content Mar-Vel Marble 202 Main Street Edmonds, WA Date: October 2017 Project No.: 1798.01 Zipper Geo Associates 19019 BORING B-2/MW-2 36th Ave. W, Suite E Lynnwood, LOG: WA Paae 2 of 2 See Figure 1, Site and Exploration Plan 41.00 feet 9/12/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries ICL between soil types. The transition may be gradual. Refer to 01 report text and appendices for additional information 0 Drillln Co an : EDI Bore Hole Dia.:6-inch Drilling Method: HSA Hammer Tltza= Auto B-3/MW-3 Drill Ria: B-61 Truck Loggedb,+L JST PENETRATION RESISTANCE (blowsifoot) ` U) en J E u AL Standard Penetration Test o 0) 8 Hammer Weight and Drop: V m E2� �Q 2 a F- U) CD 0 20 40 60 Medium dense, moist, mottled gray -brown, silty SAND, trace-- 18" to some gravel, no odor, PID <1 ppm. (Weathered Glacial Till) 1 Dense, damp, gray, sandy SILT, some gravel, no odor, PID <1 s-2 18" 5 ppm. (Glacial Till) Very dense, moist, gray, silty SAND, with gravel, no odor, PID s-3 12" 10 <1 ppm. (Glacial Till) Medium dense, wet, gray with oxidation mottling, silty SAND, s-4 12" 15 some gravel, no odor, PID <1 ppm. (Glacial Till) Sample B-3/MW-3 @15 1/2-16' submitted for analysis for ` VOCs. Groundwater observed on rods at 18 1/2 feet. 0 Very dense, saturated, gray -brown with oxidation mottling, s-5 I W 20 silty SAND, some gravel, no odor, PID <1 ppm. (Glacial Till) Very dense, saturated, dark gray, gravelly SAND, with silt, no I s-6 I 1a odor, PID <1 ppm. (Glacial Till) SAMPLE LEGEND GROUNDWATER LEGEND I2-inch O.D. split spoon sample EE Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING K Blank Casing GSA = Grain Size Analysis Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis _ on date of Consol. = Consolidation Test N measurement. Att. = Atterberg Limits i i i i i i i 3IM 30 33 75 30 50/3" , 75 O % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit i 8 --1 Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-31MW-3 19019 36th Ave. W, Suite E LOG: Lynnwood, WA 1 of 2 See Figure 1, Site and Exploration Plan 41.00 feet 9/12/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries m between soil types. The transition may be gradual. Refer to C' I report text and appendices for additional information Drilling Cv an : EDI Sore Hole Dia.: 6-inch Drilling Method: HSA Hammer Type: Auto 13-31MW-3 Drill Rig: B-61 Truck Logged bv: JST L PENETRATION RESISTANCE (blows/foot) E w z �°A Standard Penetration Test w 0 m J Z ° Hammer Weight and Drop: U E Q 0 0 m 0 n 9n 4n 60 25 Very dense, saturated, dark gray, silty GRAVEL with sand, no s_7 18" odor, PID<1ppm.lChacialTift -------------------- Very dense, saturated, gray -brown, gravelly SAND, some silt, s 8 T 18" no odor, PID <1 ppm. (Glacial Advance Outwash) 1 Sample B-3/MW-3 @ 28 112-29' submitted for analysis for 30 VOCs. Very dense, saturated, gray -brown, SAND, some silt, no odor, s-s 15" PID <1 ppm. (Glacial Advance Outwash) 35 Very dense, saturated, gray, SAND, trace to some silt, trace V) 12" 1 gravel, no odor, PID <1 ppm. (Glacial Advance Outwash) 1 Boring completed at about 36 112 feat. Groundwater observed at approximately 18 1/2 feet ATD bgs. Groundwater measured at 16.15 feet on 9112/17, immediately after well installation, from TOC. Groundwater measured at 16.22 feet on 9/14/17 from TOC. 40 Groundwater measured at 16.52 feet on 10/2/17 from TOC. Ecology Well Tag ID # BIZ 381. 45 50 SAMPLE LEGEND GRQ N WATER_L.EGEND I2-inch O.D. split spoon sample'_:] Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY ❑ Blank Casing GSA = Grain Size Analysis Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis _ on date of Consol. = Consolidation Test measurement. Att. = Atterberg Limits i 1 I I 62 62 50/3" 56 O % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit IE) --� Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-3/MW-3 19019 36th Ave. W, Suite E LOG; Lynnwood, WA Page 2 of 2 See Figure 1, Site and Exploration Plan 41.32 feet 9/12/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries m between soil types. The transition may be gradual. Refer to 01 report text and appendices for additional information 0 Drilling Company: EDI Bore Hole Dia.: 6-inch Drilling Method' HSA HammerTvoe: Auto B-4/MW Drill Rig; B-61 Truck Logged by: JST ` U PENETRATION RESISTANCE (txomdfoot) .y+ J/ Standard Penetration Test o 0) d 1 Hammer Weight and Drop: U E o �Q o C/) U 0 20 40 60 m Very dense, moist, light brown, SAND with silt and gravel, no s-1 I 15" odor, no PID. (Glacial Till) 5 Very dense, damp, light brown, sandy SILT, with gravel, no 3-2 16" odor, PID <1 ppm. (Glacial Till) Very dense, damp, light brown, sandy SILT, with gravel, no s-3 16 10 T odor, PID <1 ppm. (Glacial Till) 1 15 Very dense, moist to wet, mottled light brown with gray, silty s-4 12" I SAND, with gravel, no odor, PID <1 ppm. (Glacial Till) 20 Very dense, wet, light brown with oxidation, silty SAND, trace s-5 181. ` gravel, no odor, PID <1 ppm. (Glacial Till) Very dense, wet, light brown mottled with gray, silty SAND, s-6 I 12" with gravel, no odor, PID <1 ppm. (Glacial Till) SAMPLE LEGEND I2-inch O.D. split spoon sample 0 Clean Sand 3-inch I.D. Shelby tube sample 01 Bentonite M Grout/Concrete Screened Casing TESIING KEY ❑ Blank Casing GSA = Grain Size Analysis Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis �2 on date of Consol. = Consolidation Test � measurement. Att. = Atterberq Limits �1 ■ IIII111111 57 57 70 54 59 , 50l6" 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit = " � Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-41MW-4 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Paae 1 of 2 See Figure 1, Site and Exploration Plan 41.32 feet 9/12/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries CL aa) between soil types. The transition may be gradual. Refer to report text and appendices for additional information. 25 Very dense, wet, light gray mottled with brown, trace oxidation, silty SAND, trace gravel, no odor, PID <1 ppm. (Glacial Till) -------------------------------------------- Very dense, saturated, light brown. SAND, trace silt with gravel, no odor, PID <1 ppm. (Glacial Advance Outwash) 30 Very dense, saturated, light brown. SAND, trace silt and gravel, no odor, PID <1 ppm. (Glacial Advance Outwash) 35 40 45 Very dense, saturated, light brown, SAND, some silt, interbed of sandy fine GRAVEL_ from 35 1/2 to 36 feet, no odor, PID <1 ppm. (Glacial Advance Outwash) Boring completed at about 36 1/2 feet, Groundwater observed at about 19 1/2 feet bgs ATD. Groundwater measured at 16.99 feet below TOC on 9/12/17, immediately after well installation. Groundwater measured at 17.07 feet below TOC on 9114117. Groundwater measured at 17.39 feet below TOC on 10/2/17. Ecology Well ID: BIZ 382 50 SAM LE LEGEND I2-inch O.D. split spoon sample 3-inch I.D. Shelby tube sample TESTINGfSE GSA = Grain Size Analysis 20OW = 200 Wash Analysis Consol. = Consolidation Test Att. = Atterberg Limits Drilling Compaq; EDI Bore Hale Dia_: 6-inch DO Ing Method; HSA Hammer Type: Auto Drill Ri B-61 Truck Logged by-, JST PENETRATION RESISTANCE (blows/foot) rn °' E w zcu J > A Standard Penetration Test Z 0 - 8 -0 A Hammer Weight and Drop: GROUNDW TERL €ND Clean Sand Bentonite Grout/Concrete Screened Casing Blank Casing Groundwater level at _ time of drilling (ATD) or Q on date of i' measurement. E Q a N U) o C7 0 sa S-9 I 20 40 cn c O O C U .� o �- 60 m 7s 54 58 51 0 % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-4/MW-4 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Paae 2 of 2 See Figure 1, Site and Exploration Plan 41.20 feet 9/12/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries 0 between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Drilling Company- EDI Bore Hole Dia.: 6-inch Drilling MeM -,, HSA Hammer Type: Auto B-R Drill Rig: B-61 Truck Logged by; JST PENETRATION RESISTANCE (blows/toot) ` W E J A Standard Penetration Test o Z a ° Hammer Weight and Drop: U E 0� Q 7 2 3 ° U) C7 0 20 40 60 m Moist, light brown mottled with oxidation, silt SAND, no odor, I g Y s_1 2 3„ PID <1 ppm. (Blow counts overstated, pounding on rock) , l { (Weathered Glacial Till) i I I I _----------------------------------------- -- -5 No recovery. (Based on drilling action and observed cuttings, S_2 I ° sample likely driven into silty SAND). (Glacial Till)11-- ' k ; I II1 11WhilllH111 kf 10 Very dense, moist, light brown, silty GRAVEL, with sand, no S"3 T 6 odor, PID <1 ppm. (Glacial Till)aLL `• i - a I S-4 18"-�;�: I I I I I I Dense, moist to wet, light gray to brown with oxidation, silty SAND, some gravel interbedded with sandy GRAVEL some silt, no odor, PID <1 ppm. (Glacial Till):; Dense to very dense, moist, light brown mottled with oxidation, 20 silty SAND, no odor, PID <1 ppm. (Blow counts overstated, T pounding on rock) (Glacial Till) S-5 I 12" Boring completed at about 21 feel. 1 Perched groundwater encountered at about 15 1/2 feet bgs ATD. Groundwater measured at 16.25 feet below TOC on 9/14/17. Groundwater measured at 16.61 feet below TOC on 1012/17. Ecology Well ID: BIZ 383 25 SAMPLE LEGEND D DWATER LE END I2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grouticoncrete Screened Casing TESTING KBlank Casing GSA = Grain Size Analysis VGroundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis N on date of Consol. = Consolidation Test N measurement. Att. = Atterberq Limits 50/6" 50/6" 33 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit 1 e 1 Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING 13-5/MW-5 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 1 of 1 Boring Location- See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 6-inch Top Elevation: 39.17 feet Drilling Method' HSA H, mmer Type. Auto B-6/MW-6 Date Drilled: 9/1312017 Drill Ri : B-61 Truck Lagaed by- JST SOIL DESCRIPTION `m PENETRATION RESISTANCE (blows/toot) co W M Standard Penetration Test o The stratification lines represent the approximate boundaries Z Q Hammer Weight and Drop: CJ m between soil types. The transition may be gradual. Refer to E (2 :3 o report text and appendices for additional information. � m 0 20 40 60 0 li i' Il 111 II l Medium dense, moist, gray to brown mottled with oxidation, silty SAND, with gravel, no odor, PID <1 ppm. (Weathered Glacial Till) ri Very dense, damp, gray, sandy SILT, some gravel, no odor, PID <1 ppm. (Glacial Till) Very dense, moist, gray, silt SAND, with gravel, no odor, PID s-3 12" I ! ; i 10 T f <1 ppm. (Glacial Till) 1 I - 15 Very dense, wet, light brown, silty SAND, interbedded with gray, SAND with silt, some gravel, no odor, PID <1 ppm. (Glacial Till) 20 Very dense, wet, gray to brown, SAND, with silt and gravel, interbedded with silty SAND, no odor, PID <1 ppm. (Glacial Till) Very dense, wet, blue to gray, sandy SILT, no odor, PID <1 ppm. (Glacial Till) 25 SAMPLE LEGEND QRQUN0WATEfR L GEND I2-inch O.D. split spoon sample E"iei Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY ❑ Blank Casing GSA = Grain Size Analysis Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test N measurement. Att. = Atterberq Limits mom W�W1'�� 1111lI ►� l 1 30 68 55 60 .. o O % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit I 1 Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-6/MW-6 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 1 of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 6-inch Too Elevation_ 39.17 feet Drilling Method: HSA Hammer7yoe_ Auto B-6/MW-6 Date Drilled: 9/13/2017 Drill Rig: B-61 Truck Logged IM JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) $ Standard Penetration Test C o a The stratification lines represent the approximate boundaries p pp J z 0 ' c 0 Hammer Weight and Drop: U } between soil types. The transition may be gradual. Refer to E Q � : o � Q report text and appendices for additional information. � m 0 20 40 60 25 Very dense, saturated, blue to gray, gravelly SILT, with sand, s-7 9" f �"�"; I �50/3"ri no odor, PID <1 ppm. (Glacial Till)-�-u�j '� -� '�' j— j Very dense, saturated, blue to gray, SILT, with sand, trace gravel, no odor, PID <1 ppm. (Glacial Till) S-8 I 10, -------------------------------------------- Dense, saturated gray, SAND, trace silt and gravel moderate S-9 T 1 odor, PID <1 ppm. (Unusual odor unlike typical hydrocarbon .IL odor. Smelled sickly sweet and herby) (Glacial Advance Outwash) T Dense, saturated, gray, SAND, trace silt and gravel, moderate 3-10 I 1 odor, PID <1 ppm. (Same unusual odor as above) (Glacial 1 Advance Outwash) 35 T Very dense, saturated, gray, SAND, trace silt and gravel, s-11 I 181, moderate odor, PID=57.2 ppm. (Same unusual odor as 1 above) (Glacial Advance Outwash) T Very dense, saturated, gray, SAND, trace silt and gravel, no s-12 I 181, odor, PID <1 ppm. (Glacial Advance Outwash) Boring completed at about 38 1 /2 feet. Groundwater observed at about 24 1/2 feet bgs ATD. 40 Groundwater measured at 14.29 feet below TOC on 9/12/17. Groundwater measured at 14.61 feet below TOC on 10/2/17. Ecology Well ID: BIZ 384 F 45 50 SAMPLE LEGEND GROUNDWATER LEGEND I2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/concrete Screened Casing TESTING KEY ❑ Blank Casing GSA = Grain Size Analysis 7 Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test N measurement. Att. = Atterberg Limits n I-� I I 50/4" 33 46 56 63 0 % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit f a_ Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-6/MW-6 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 2 of 2 Baring Location' See Figure 1, Site and Exploration Plan Drilling CompanEDI Bore Hole Dia.: 6-inch Top Flmfion: 39.08 feet Driilina Method: HSA Hammer_Ty: Auto B-7/MW-7 Date Drilled: 9/13/2017 Drill Riq: B-61 Truck Logged bv: JST SOIL DESCRIPTION PENETRATION RESISTANCE (binwslfaot) N EJ A Standard Penetration Test o s The stratification lines represent the approximate boundaries Z D a Hammer Weight and Drop: U a)between soil types. The transition may be gradual. Refer to o H report text and appendices for additional information. m 0 20 40 60 0 i. mJ Medium dense, damp, mottled gray -brown with some S-1 I 1s oxidation, silty SAND, no odor, PID <1 ppm. (Weathered Glacial Till) 5------------------------------------------- Dense, damp, gray -brown, silty SAND, no odor, PID <1 ppm. S-2 (Glacial Till) 11 Dense, damp, gray, gravelly SAND, with silt, PID=9.6 ppm. S-3 1s 10 j' (Slight hydrocarbon odor) (Glacial Till) 1II Dense, wet, gray, silty SAND, trace gravel, no odor, PID=8.4 T Wit: 9 s-a ppm. (Glacial Till) f 201 Very dense saturated, gray, SAND, with gravel and silt, no odor, PID <1 ppm. (Glacial Till) Boring completed at about 21 feet bgs. Groundwater observed at about 19 feet bgs ATD. Groundwater measured at 14.01 feet below TOC on 9/14/17. Groundwater measured at 14.31 feet below TOC on 10/2/17. Ecology Well ID: BIZ 385 25 SAMPLE LEGEND GROUNDWATM LEQEND I2-inch O.D. split spoon sample Is;; Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING ❑ Blank Casing GSA = Grain Size Analysis Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis N on date of Consol. = Consolidation Test N measurement. Att. = Atterberg Limits _ I I S-5 I 12" 21 45 47 ■�10Ium � 'I!I I illlll ! III'I 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-7/MW-7 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 1 of 1 � 'I!I I illlll ! III'I 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-7/MW-7 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 1 of 1 Serino Location' See Figure 1, Site and Exploration Plan ao EleYatlan: 42.62 feet )ate Drilled: 9/13/2017 SOIL DESCRIPTION The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. 0 Drilling ComnanV: EDI Bore Hale Dia.: 6-inch Drilling Method: HSA Hammer T 1�e: Auto Drill Rig: B-61 Truck Longed by: JST U) `i PENETRATION RESISTANCE (bloc 'AGot) LLI �6 Standard Penetration Test E a� -a Hammer Weight and Drop: E (n U 0 Poor recovery, brown, moist, sandy GRAVEL, with silt, no odor. (Blow counts overstated, pounding on rock) (Based on s-1 drilling action and observed cuttings we interpret up to 4 feet of weathered tilltweathered till fill in this Iocation) -- No recovery. (Based on drilling action and observed cuttings 5 we interpret a glacial till contact at about 4 feet bgs) I 10 s-3 2 3° Very dense, damp, gray -brown, silty SAND, with gravel, no odor, PID <1 ppm. (Glacial Till) 15 Very dense, moist to wet, mottled gray and brown with s-4 oxidation, silty SAND, with gravel, no odor, PID <1 ppm. (Glacial Till) 20 Very dense, grades to saturated at about 19 feet, mottled gray and brown with oxidation , silty SAND, with gravel, no odor, PID <1 ppm. (Glacial Till) s-5 14° 25 Boring completed at about 21 1/2 feet. Groundwater observed at about 18.5 feet bgs ATD. Groundwater measured at 17.61 feet below TOC on 9/12/17. Groundwater measured at 18.00 feet below TOC on 10/2/17. Ecology Well Tag ID: BIZ 386 SAMPLE LEGEND I2-inch O.D. split spoon sample 3-inch I.D. Shelby tube sample TESTING KEY GSA = Grain Size Analysis 20OW = 200 Wash Analysis Consol. = Consolidation Test Att. = Atterberg Limits GROUNDWATER LEGEND Clean Sand Bentonite Grout/Concrete Screened Casing ❑ Blank Casing Groundwater level at _ time of drilling (ATD) or N on date of 1' measurement. 20 40 I i i IN 10 1� 50/31, 37 50/3" ,50r5" , 86 0 % Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-81MW-8 19019 36th Ave. W, Suite E I LOG: Lynnwood, WA 1 of 1 Soring Location: See Figure 1, Site and Exploration Plan Drilling Company, EDI Bore Hole Dia.:6-inch Ton Elevation: 40.82 feet Drif in Method: HSA Hammer Tyne: Auto B-9/MW-9 Date Drilled: 9/14/2017 Drill Rig_ B-61 Truck Loosed bk-. JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) N E J A Standard Penetration Test o The stratification lines represent the approximate boundaries Z 'g v Hammer Weight and Drop: CJ rn a) between soil types. The transition maybe gradual. Refer to E o � report text and appendices for additional information. (n m Q 20 40 60 0 I Medium dense, moist, gray -brown, silty SAND, some gravel, s_1 T 12„ - 26 no odor, PID <1 ppm. (Weathered Glacial Till) 1 _ 3 Medium dense, moist, gray -brown, silty SAND, some gravel to j :• f 5 about 5 1/2 feet. T Medium dense, moist gray -brown, SAND, some silt, no odor, s-z I 1s 20 PID <1 ppm. (Glacial Outwash) I j it Very dense, moist, gray with oxidation, silty SAND, some I gravel (Glacial Till). s-3 14" 1 ! 1 67 Very dense, moist, gray, SAND, some silt and gravel, no odor, I I I 1 o X, PID<i ppm. Vertical contact at 8 112 feet, silky SAND with `'` I { some oxidation along contact. (Glacial Outwash) f S-4 16" i 1 I 4 �_ I ► 73 ----------------------------------------- 1 F-- ` it Very dense, damp to moist, gray, silty SAND, with gravel, no odor, PID <1 ppm. (Glacial Till) j ?:—? LL 50r6" Very dense, damp to moist, mottled gray and brown, silty s-5 I 12 j GRAVEL, with sand, no odor. (Glacial Till) t� I j 20 T Very dense, saturated, gray -brown, SAND, with silt, some s_6 I 16„ :::;; i I i 75 gravel, no odor, PID <1 ppm. (Glacial Till) 1 = I I I Groundwater observed at about 18 1/2 feet bgs ATD. Groundwater measured at 14.73 feet below TOC on 9/14/17. Groundwater measured at 15.99 feet below TOC on 10/2/17. 25 1 W II ID: BIZ 387 SAMPLE LEGEND GROUNDWATER LEGEND I2-inch O.D. split spoon sample ED, Clean Sand 3-inch I.D. Shelby tube sample 01 Bentonite Grout/concrete Screened Casing TESTING KEY ❑ Blank Casing GSA = Grain Size Analysis '� Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis _ on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits O % Fines (<0.075 mm) O % Water (Moisture) Content Plastic Limit Iaj Liquid Limit Natural Water Content Mar-Vel Marble 202 Main St. Edmonds, WA Date: October, 2017 Project No.: 1811.22 Zipper Geo Associates BORING B-9/MW-9 19019 36th Ave. W, Suite E LOG: Lynnwood, WA Page 1 of 1 ZIPPER OEO ASSOCIATES, LLC 19019 36`h Avenue West, Suite E, Lynnwood, Washington 98036 Test Pit Log TP-1A Project: Mar-Vel Marble Location: See Site and Exploration Plan, Figure 1 Project No: 1811.22 Approx. Ground Surface Elevation: 38 feet Date Excavated: 08/21/2017 Depth Material Description Sample PID Odor (ft) (ppm) Loose, damp, dark brown, SAND, with silt and organics 1 (SANDY TOPSOIL) ....................................... Medium dense, damp, brown, SAND, with silt and gravel, some organics, oxidation mottling from 1 to 3 feet bgs (WEATHERED GLACIAL TILL) ...................................... 2 3 221 Slight 4 Very dense, moist, light brown, sandy SILT, with gravel (Glacial Till) Some perched groundwater in sand lens at 4 5 feet bgs. Transitions to gray at 4 feet and below. Color change coincides with moderate odor of TPH. 6 Discoloration and odor most distinct in north sidewall. Moderate to strong odor of TPH from approximately 4 to 10 feet bgs in north sidewall. 7 TP-1A @7' 1647 Strong 8 9 TP-1A, S-Side @10' 7.1 Mod, 10 Odor decreases to slight below 10 feet bgs in north sidewall. 11 12 13 7.2 Slight to none Odor decreases to trace below 13 feet bgs in north 14 sidewall. 15 Field indications of PCS extend to the south of the north sidewall for approximately 10 feet in a zone between 6 16 and 10 feet bgs. 17 Test pit completed at about 18 feet bgs. per groundwater observed at about 4 feet bgs. 18 1.3 Slight to none ZIPPER GEG ASSOCIATES, LLC 19019 36" Avenue West, Suite E, Lynnwood, Washington 98036 Test Pit Log TP-1B Location: See Site and Exploration Plan, Figure 1 Approx. Ground Surface Elevation: 38 feet Project: Mar-Vel Marble Project No: 1811.22 Date Excavated: 08/21/2017 Depth (ft) Material Description Sample PID (PPm) Odor 1 Loose, damp, dark brown, SAND, with silt and organics (SANDY TOPSOIL) .. . ...................... Medium dense, damp, brown, SAND, with silt and gravel, some organics, oxidation mottling from 1 to 3 feet bgs (WEATHERED GLACIAL TILL) ...................................... Very dense, moist, light brown, sandy SILT, with gravel (Glacial Till). Some perched groundwater in sand lens at 4 feet bgs. Transitions to gray at 4 feet and below. Color change coincides with moderate odor of TPH. Discoloration and odor most distinct in north sidewall. Moderate to strong odor of TPH from approximately 4 to 10 feet bgs. Field indications of PCS extend approximately 15 feet from west sidewall of excavation at a depth of approximately 4 to 10 feet bgs. 2 3 4 5 6 7 8 9 10 TP-113, E-Side @10' 1.7 Slight to none 11 12 Test pit completed at about 12 feet bgs. Perched groundwater observed at about 4 feet bgs. 13 14 15 16 17 18 ZIPPER GEG ASSOCIATES, LLC 19019 36" Avenue West, Suite E, Lynnwood, Washington 98036 Test Pit Log TP-2A Project: Mar-Vel Marble Location: See Site and Exploration Plan, Figure 1 Project No: 1811.22 Approx. Ground Surface Elevation: 40 feet Date Excavated: 08/21/2017 Depth Material Description Sample PID Odor (ft) (ppm) Loose, damp, dark brown, gravelly SAND, with silt and 1 organics (SANDY TOPSOIL)* Medium dense, damp, light brown, gravelly SILT, with sand (WEATHERED GLACIAL TILL)* <1 None 2 <1 None '...................................... 1.1 None 3 Very dense, damp, light brown, gravelly SILT, with sand (GLACIAL TILL)* 4 Gray discoloration and odor from 4 % to 9 % feet bgs 43.3 Moderate 5 along edges of heating oil UST cavity and directly below the UST cavity. Field indications of TPH extended 6 approximately 10 to 15 feet beyond the edges of the UST cavity to the east and west at a depth of approximately 5 TP-2A, E-side@7' < 1 7 to 8 feet bgs. TP-2A, W-side@7' 1.1 TP-2A@8' 8 Very dense, damp, light brown, sandy GRAVEL, with silt (GLACIAL TILL) 232.7 Strong 9 TP-2A@10' 27.6 Moderate 10 1.9 Slight 11 12 Test pit completed at about 10 %2 feet bgs. No groundwater observed during excavation. 13 * TP-2A transected the north edge of heating oil UST cavity. We observed pea gravel backfill in the central 14 approximately 8 feet of the southern edge of the test pit to a depth of approximately 5 % feet. 15 16 17 18 ZIPPER GEO ASSOCIATES, LLC 19019 36`h Avenue West, Suite E, Lynnwood, Washington 98036 Test Pit Log TP-213 Project: Mar-Vel Marble Location: See Site and Exploration Plan, Figure 1 Project No: 1811.22 Approx. Ground Surface Elevation: 40 feet Date Excavated: 08/21/2017 Depth Material Description Sample PID Odor (ft) (ppm) Loose, damp, dark brown, gravelly SAND, with silt and 1 organics (SANDY TOPSOIL)* Medium dense, damp, light brown, gravelly SILT, with sand (WEATHERED GLACIAL TILL)* None 2 None ...................................... .Very None 3 dense, damp, light brown, gravelly SILT, with sand (G LACIAL TI LL) * Moderate 4 Gray discoloration and odor from 4 % to 9 % feet bgs 5 along edges of heating oil UST cavity and directly below the UST cavity. Field indications of TPH extended 6 approximately 10 to 15 feet beyond the edges of the UST cavity to the north and south at a depth of approximately 7 5 to 8 feet bgs. Moderate Tp-2B, S-Side@8' 2.2 (South) 8 Very dense, damp, light brown, sandy GRAVEL, with silt TP-26, N-Side@8' < 1 (North) (GLACIAL TILL) Moderate 9 10 11 12 Test pit excavation completed at about 10 %: feet bgs. No groundwater observed during excavation. 13 * TP-213 transected the heating oil UST cavity. We observed pea gravel backfill in the central approximately 14 g feet of the test pit to a depth of approximately 5 % feet. 15 16 17 18 ZIPPER CEO ASSOCIATES, LLC 19019 36`h Avenue West, Suite E, Lynnwood, Washington 98036 Test Pit Lag TP-3 Location: See Site and Exploration Plan, Figure 1 Approx. Ground Surface Elevation: 38 feet Project: Mar-Vel Marble Project No: 1811.22 Date Excavated: 08/21/2017 Depth (ft) Material Description Sample PID (ppm) Odor 1 Loose, damp, brown, silty SAND, with organics (SANDY TOPSOIL) Dense, damp, light brown with oxidation mottling, silty SAND, with gravel (WEATHERED GLACIAL TILL) 2 3 4 1.2 Test pit excavation completed to about 3 %Z feet bgs. No field indications of PCS. No groundwater observed during excavation. 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ZIPPER GEO ASSOCIATES, LLC 19019 36`h Avenue West, Suite E, Lynnwood, Washington 98036 Test Pit Log TP-4 Project: Mar-Vel Marble Location: See Site and Exploration Plan, Figure 1 Project No: 1811.22 Approx. Ground Surface Elevation: 43 feet Date Excavated: 08/21/2017 Depth Material Description Sample PID Odor (ft) (ppm) Medium dense, damp, light brown, silty SAND, with 1 gravel, some oxidation mottling (WEATHERED GLACIAL TILL) None 2 ........................................ Very dense, damp, light brown, silty SAND, with gravel Slight (GLACIAL TILL) 3 Localized pea gravel from approximately 1 to 6 feet bgs. 4 Field indications of PCS from approximately 2 to 7 feet bgs Moderate 5 and radially approximately 3 to 5 feet from the edges of the hoist cavity. Gray discoloration and a slight to 6 moderate odor. <1 TP-4, E-Side@6.5' 28.8 7 TP-4@7' Moderate TP-4, N-Side@7' 2.2 Slight to 8 Light brown, damp, very dense, sandy GRAVEL, with silt TP-4, W-Side@8' none 9 10 (GLACIAL TILL) 11 12 13 14 15 16 Test pit completed at about 16 % feet bgs. 17 Backfilled with clean soil below 8 feet. Backfilled with PCS above 8 feet. 18 Groundwater not observed during excavation. APPENDIX B LABORATORY TESTING PROCEDURES AND RESULTS LABORATORY TESTING PROCEDURES A series of laboratory tests were performed during the course of this study to evaluate the index and geotechnical engineering properties of the subsurface soils. Descriptions of the types of tests performed are given below. Visual Classification Samples recovered from the exploration locations were visually classified in the field during the exploration program. Representative portions of the samples were carefully packaged in moisture tight containers and transported to our laboratory where the field classifications were verified or modified as required. Visual classification was generally done in accordance with ASTM D-2488. Visual soil classification includes evaluation of color, relative moisture content, soil type based upon grain size, and accessory soil types included in the sample. Soil classifications are presented on the exploration logs in Appendix A. Photoionization Detector Recovered soil samples were also screened in the field shortly after collection with a hand held Photoionization Detector (PID) to evaluate the presence or absence of Volatile Organic Compounds (VOCs). PID readings are presented on the exploration logs in Appendix A in parts per million (ppm). Moisture Content Determinations Moisture content determinations were performed on representative samples obtained from the explorations in order to aid in identification and correlation of soil types. The determinations were made in general accordance with the test procedures described in ASTM D-2216. Moisture contents are presented on the exploration logs in Appendix A. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses were performed on representative samples in general accordance with ASTM: D-422. The results of the grain size determinations for the samples were used in classification of the soils, and are presented in this appendix. 100 = 80 W ?� 70 m 60 W Z F- 50 Z W W 40 W a 30 20 10 GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER 1111111111111 Ills iiiiiislillillislilliill.,,IllllI 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-1 S-3 7.5 11.5 40.3 Silty SAND some gravel Project No.: 1798.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 5/1/2017 Graphite Studios 100 ffl = 80 t� w 70 m IW 60 W Z LL 50 Z W W 40 W a 30 20 10 GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 inn 11111111111111111111111111111111111 u 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-1 S-5 15 11.8 46.6 Silty SAND some gravel Project No.: 1798.01 PROJECT NAME: Zi er Gea Associates LLC Geotechnical and Environmental consultants DATE OF TESTING: 5/1/2017 Graphite Studios 100 = 80 0 w 70 m W 60 W Z 50 Z W V W 40 W a 30 20 10 GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 SIZE OF OPENING IN INCHES iU.S. STANDARDSIEVE SIZE ATDROffiETER oil 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Coarse I Medium !! Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-1 S-8 30 21.0 5.3 SAND, some silt, trace gravel Project No.: 1798.01 PROJECT NAME: Zipper Geo Associates LLC Geotechnical and Environmental Consultants DATE OF TESTING: 5/1/2017 Graphite Studios 100 = 80 (9 70 m W 60 W Z F- 50 Z W () IW 40 W a 30 20 10 GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 SIZE OF OPENING IN INCHES II.S. STARDARD SIET'E—STZE- 1111111111111111 milli u 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Silt Clay BOULDERS COBBLES GRAVEL SAND FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description g-2 S-6 20 9.6 25.4 SAND with silt and gravel Project No.: 1798.01 PROJECT NAME: Zipper Geo Associates LLC Geotechnical and Environmental Consultants DATE OF TESTING: 5/20/2017 Graphite Studios