202 ALDER ST Geotech Report 2025-07-30

Limited Geotechnical Engineering Study View Ridge Elementary School Portable Classroom Installation Everett, Washington and Downspout Infiltration Feasibility current portable classroom placement task. The 2010 explorations encountered existing fill up to 10 feet thick overlying dense granular sediments interpreted as Vashon advance outwash. The fill observed in our previously completed exploration borings was considerably thicker in EB-1 (10 feet) and EB-3 (8.5 feet) than elsewhere onsite; otherwise, the borings completed for the referenced geotechnical report are consistent with the recent borings. New Exploration Borings For the current study three new exploration borings were completed by Geologic Drill Partners, an independent firm working under subcontract to AESI, at the locations shown on Figure 2. The borings were completed by advancing a 6-inch outside-diameter, hollow-stem auger with a small, tracked drill rig. During the drilling process, samples were generally obtained at 21/2- to 5-foot-depth intervals. The borings were continuously observed and logged by a geologist from our firm.The exploration logs presented in Appendix A are based on the field logs,drilling action, and observation of the samples collected. Disturbed but representative samples were obtained by using the Standard Penetration Test (SPT) procedure in accordance with ASTM International (ASTM) D-1586. This test and sampling method consists of driving a standard 2-inch, outside-diameter, split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches.The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance ("N")or blow count. If a total of 50 is recorded within one 6-inch interval,the blow count is recorded as the number of blows for the corresponding number of 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 logs. 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 and laboratory testing, as necessary. SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from our field explorations accomplished for this study, visual reconnaissance of the site, and review of selected applicable geologic literature. July 12,2023 ASSOCIATED EARTH SCIENCES,INC. acv/kd-20100255E004-002 Page 3