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Geotechnical Engineering Report SSGC <br /> Hardeson Road Retail <br /> Everett,Washington <br /> SSGC Project No. 18072 <br /> September 18,201.8 <br /> i <br /> SUBSURFACE CONDITIONS <br /> Subsurface conditions were characterized by completing five test pits and one infiltration test on.August <br /> 30, 2018. Test pits were advanced to final depths between 12 and 21 feet below existing ground surface. <br /> Approximate locations of the explorations are shown on Figure 1, Exploration Plan. A summary <br /> description of observed subgrade conditions is provided below. Logs of the test pits are provided in <br /> Appendix A. <br /> Soil Conditions <br /> Fill was observed in all of the test pits and consisted of mixed sand,silt, gravel,organics,cobbles, <br /> boulders and various debris. It was generally in a loose to medium dense condition and extended <br /> to depths between 1 and 20.5 feet at the test pit locations. Fill thickness is expected to vary <br /> across the site and may be thicker than observed in the test pits. Fill is anticipated to be thicker 1 <br /> along the northern portion of the site. <br /> Topsoil was observed below the fill in test pits TP-I in the southeastern portion of the site and I <br /> was about 1 foot thick. <br /> Native soil below the topsoil consisted of silty sand with gravel and variable cobbles and. clay. I <br /> Most of these soils were in a medium dense to dense condition and interpreted as glacial till. In <br /> test pits TP-3 and T.P-5, slightly cleaner(less fines)were observed in the upper native soil below <br /> the fill and may be alluvium associated with a stream channel that historically was located on the <br /> property. <br /> Groundwater Conditions <br /> Groundwater was observed only in test pit TP-5 (south central part of site) at the time of <br /> excavation. Depth to groundwater was at about 17.5 feet. Groundwater was not observed in the I <br /> other test pits, although some mottling of upper native soil was observed in the test pit TP-1 <br /> (eastern, lower elevated portion of site) was observed suggesting seasonal perched groundwater <br /> conditions. Groundwater levels should be anticipated to vary due to seasonal precipitation <br /> patterns and on-and off-site drainage patterns. <br /> Geologic Setting <br /> Native soils on the site are mapped as Alderwood Urban gravelly sandy loam per the USDA Soil <br /> Conservation Service map of Snohomish County, Washington. Alderwood soils are reportedly <br /> formed in glacial till. Most of the native soil observed in the test pits appears to conform to the <br /> mapped soil type. <br /> 1 <br /> 2 <br />