5200 EVERGREEN WAY SEPA 017 - 010 Geotech Report 2025-04-23

Subsurface Exploration, Geologic Hazards,and Former Brien Ford Preliminary Geotechnical Engineering Report Everett, Washington Project and Site Conditions inches of penetration. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils; these values are plotted on the attached exploration boring log. The samples obtained from the split-barrel sampler were classified in the field and representative portions placed in watertight containers. The samples were then transported to our laboratory for further visual classification, as summarized in this report. 3.2 Direct-Push Probes Direct-push Geoprobe drilling services were provided by ESN Northwest of Olympia, Washington. An AESI field representative observed drilling activities and collected soil, soil gas, and reconnaissance ground water samples for laboratory analysis. Push-probe explorations were completed on November 9 and 10 of 2016, February 13, 2017, and March 9, 2017 at the project site. The sampler was lined with disposable plastic sleeves that were removed and opened to reveal the sample for each 5-foot driven interval. Soil samples were described and continuously logged in general accordance with the Unified Soil Classification System (USCS) and field-screened for potential evidence of contamination. Field-screening included making visual observations and notations of odor, and conducting headspace analysis using a photoionization detector (PID) to detect the presence of volatile organic compounds (VOCs). Two soil samples were collected from each boring in 1-foot intervals. In general, sample intervals were selected using the field-screening methods to vertically delineate contamination found. If no indications of contamination were found, AESI sampled the soil interval just below the pavement and the deepest soil sample interval. The push-probe logs provide a qualitative relative density for the encountered sediments which is based on drill action in the field. These densities are not correlated to SPT data as is the case for the hollow-stem auger boring, EB-1, completed for this study. 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field exploration accomplished for this study, review of previously completed explorations at the site, visual reconnaissance of the site, and review of selected applicable geologic literature. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions in the vicinity of the explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. May 16,2017 ASSOCIATED EARTH SCIENCES,INC. AWR/d-160594V003-1-Projects1101605941KV\WP Page 3