11229 19TH AVE SE SILVER LAKE TOWNHOMES WHOLE SITE Geotech Report 2022-10-25

Geotechnical Report Proposed Development: 11229 - 19th Avenue SE, Everett, WA September 16, 2016 samples are obtained using a 2-inch outside diameter split-spoon sampler. The sampler was driven into the soil a distance of 18 inches using a 140-pound weight freely falling a distance of 30 inches. The number of blows required for each 6-inch increment of sampler penetration was recorded. The number of blows required to achieve the last 12 inches of sample penetration is defined as the SPT N-value. The N-value provides an empirical measure of the relative density of cohesionless soil, or the relative consistency of fine-grained soils. The soils were logged in general accordance with ASTM D-2487 Standard Practice for Classification of Soils for Engineering Purposes and the system summarized on Figure A-1,Terms and Symbols for Boring and Test Pit Logs. Summary boring logs are included as Figures A-2 through A-5. 4.0 SUBSURFACE CONDITIONS 4.1 SITE GEOLOGY According to The Geologic Map of the Everett 7.5 Minute Quadrangle, Snohomish County, Washington (Minard, 1985), the primary geologic unit in the vicinity of the site is Vashon Till (Geologic Map Unit Qvt). Vashon Till consists of an unsorted deposit (diamict) of clay, silt, sand and gravel that has been glacially transported, deposited and consolidated. Till is typically dense to very dense and is well suited for support of structural loads. 4.2 SOIL CONDITIONS For a detailed description of the subsurface conditions encountered at each exploration location, please refer to our boring logs provided in Appendix A. The stratigraphic contacts indicated on the boring logs represent the approximate depth to boundaries between soil units. Actual transitions between soil units may be more gradual or occur at different elevations. The descriptions of groundwater conditions and depths are likewise approximate. The following is a generalized description of the soils encountered in the borings. UNIT 1:Fill—Fill was encountered from surface to about 3 to 8 feet in borings PG-1, PG- 3, and PG-4. Fill was not encountered in boring PG-2. Fill is the deepest at PG-1 that extended to about 8 feet below the surface. The fill encountered generally consisted of very loose to medium dense, slightly gravelly, silty sand and sandy silt. It is characterized by its mottled color and texture and trace organic debris. 16-210 11229 19th Ave SE Rpt Page 3 PanGEO, Inc.