2320 106TH ST SW Geotech Report 2022-10-25

October 14,2015 Project No.T-6116-2 • Foundation support • Slab-on-grade floors • Stormwater detention vault • Site retaining walls • Drainage • Utilities • Pavements It should be noted that recommendations outlined in this report regarding drainage are associated with soil strength, design earth pressures, erosion, and stability. Design and performance issues with respect to moisture as it relates to the structure environment are beyond Terra Associates' purview. A building envelope specialist or contractor should be consulted to address these issues,as needed. 3.0 SITE CONDITIONS 3.1 Surface The project site consists of a single tax parcel totaling approximately 3.9 acres located south and adjacent 106th reet SW, between Airport Road and 21st Place West in Everett, Washington. The approximate site location is town on Figure 1. The site is currently undeveloped and covered with a heavy forest and associated understory. Site topography consists of a slight slope that descends from the west to the east with an overall relief of approximately eight feet. 3.2 Subsurface Soil conditions we observed in the test pits excavated in 2007 consisted of 1 '/z to 2 1/2 feet of loose to medium dense silty sand with gravel and roots (weathered till) overlying dense to very dense gray silty sand(unweathered glacial till). Based on the current surface conditions, it does not appear that any fill has been placed since we conducted the subsurface exploration in 2007. The Geologic Map of the Everett 7.5—Minute Quadrangle, Snohomish County, Washington, by James P. Minard (1995)maps the site as till (Qvt). This mapped description is consistent with the native soil we observed at depth in the test pits. The preceding discussion is intended to be a general review of the soil conditions encountered. For more detailed descriptions,please refer to the Test Pit Logs in Appendix A. Page No. 2