6202 ASSOCIATED BLVD Geotech Report 2022-10-25

Proposed Everett Warehouse ZipperGeo Project No. 2152.01 March 5, 2019 by Associated Boulevard; and to the west by developed industrial property. The site slopes gently downward to the north with a total vertical relief of about 12 feet. SUBSURFACE CONDITIONS Mapped Geology We reviewed published geologic mapping of the site vicinity through the Washington State Department of Natural Resource's web -based mapping application Washington Geologic Information Portal (https://geologyportal.dnr.wa.gov/). The published mapping indicates the site is underlain by Vashon Till. The mapping describes Vashon Till as a nonsorted mixture of clay, silt, sand, pebbles, cobbles, and boulders, all in variable amounts. The mapping further describes the Till as " It typically is hard lodgement till and often is referred to as "hardpan." The "hardpan" is largely a result of compaction caused by the great weight of the overriding ice, hundreds of meters thick." Soil Conditions Soil conditions at the site were evaluated through the completion of 10 geotechnical test pits (TP-1 to TP- 10) and three geotechnical test borings. The test pits were advanced to a depth ranging from about 5 to 13 feet below existing site grade. The borings were advanced to a depth of about 41.5 feet below existing site grade. The approximate test pit and boring locations are shown on the attached Site and Exploration Plan, Figure 1. Soils were visually classified in general accordance with the Unified Soil Classification System. Descriptive logs of the subsurface explorations and the procedures utilized in the subsurface exploration program are presented in Appendix A. A generalized description of soil conditions encountered in the test pits is presented below. Detailed descriptions of soils encountered are provided on the descriptive logs in Appendix A. Surficial soils conditions observed in the test pits generally consisted of about 3 to 10 inches of topsoil. Below the topsoil, soil conditions observe in test pits TP-1 through TP-3 generally consisted of 2 % to 8 feet of loose to dense sand with variable silt and gravel content interpreted to be undocumented fill soils. Below the fill in TP-1 through TP-3, soil conditions generally consisted of medium dense to dense silty sand with gravel and cobbles. Soil conditions observed below the topsoil in test pits TP-5 through TP-10 generally consisted of loose to dense, sand with trace to some silt and variable gravel and cobble content extending mostly to about 1.5 to 3 feet below existing site grade. However, in TP-10, this sand unit extended to about 6 feet below existing site grade. Below the sand, test pits TP-5 through TP-10 generally encountered medium dense to dense silty sand with variable gravel and cobble content to the depths explored. Soil conditions observed below the topsoil in test pit TP-4 generally consisted of medium dense to dense, silty sand with cobbles and some gravel. Soil conditions observed in borings B-1 through B-3 generally consisted of about 8 inches of topsoil underlain by medium dense to dense silty sands with variable gravel content to the completion depths of about 41.5 Page 2