2320 RAILWAY AVE Geotech Report 2023-02-01

I I Interwest Construction Co.-Everett Contractor Yard Site Improvements, Everett,WA March 12,2021 Geotechnical Engineering Report P2184-T20 I I I I I I I I I I I I The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in our test pits,based on our field classifications. 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 the in-situ soils by means of the excavation characteristics and the stability of the test pit sidewalls. Our logs also indicate the approximate depths of any sidewall caving or groundwater seepage observed in the test pits. The soils were classified visually in general accordance with the system described in Figure A-1,which includes a key to the exploration logs. Summary logs of our explorations are included as Figures A-2 through A-5. 3.0 SITE CONDITIONS The following sections present our observations, measurements, findings, and interpretations regarding surface, soil, groundwater and seismic conditions and liquefaction potential. 3.1 Surface Conditions As previously indicated,the project site consists of an irregularly-shaped,13.18-acre parcel,located at 2320 Railway Avenue, towards the northeast corner of the City Limits of Everett, Washington. The project area is situated within an industrial area west of the divergence between the Snohomish River and the Steamboat Slough,along the east side of the BNSF Railroad. The site is bound on the south by the Penske Truck Leasing site and on the east by the ROW for Railway Ave. The subject property is currently being utilized by Interwest as a service yard for its operations, containing gravel surfacing,and being occupied by heavy equipment,stockpiles of soils, construction debris and topsoil, storage containers, pallets of building materials and piping for the adjacent Railway Avenue improvements. Topographically, the project area is gently sloped, cresting towards the center of the site, with upwards of 5 feet of elevation change being observed over its extent. Vegetation onsite is limited to scattered weeds,grasses and scotch broom,as much of the property I has been cleared and graded. The project area is located in a bend of the Snohomish River, and some ponding was observed at surface elevations on the site. No other hydrologic features were observed onsite such as seeps or springs. 3.2 Soil Conditions We observed subgrade conditions through the advancement of four test pit explorations (TP-1 I through TP-4) across the site, adjacent to proposed improvements. Subgrade conditions were relatively consistent,generally consisting of a surficial cap of 5 to 6 feet of fill soils,transitioning to alluvial sands and peat. The uppermost±2 feet of fill soils across the southern portion of the site consisted of 3 to 4-inch minus recycled concrete/asphalt, compacted to a dense condition. This material was reportedly crushed on site. The remainder of the fill soils across this region consisted of"pit-run" like materials encountered in a medium dense in situ condition. Fill soils across the northern portion of the project area contained primarily the"pit run"like materials. Isolated lenses of ballast rock and/or quarry spalls were also encountered within the fill cap. Migizi Group, Inc. Page 3 of 16 .