1304 80TH ST SW EVERETT SCHOOL DISTRICT 2018-01-02 MF Import

• Subsurface Exploration and Everett Bus Facility G..nechnical Engineering Report Everett, Washington Project and Site Conditions 3.1 Exploration Borings Exploration boring, were advanced with a Mobile B61 truck-mounted drill rig. The borings permitted limited visual observation of subsurface conditions. Representative samples of the soils encountered were obtained f. im the borings using the Standard Penetration Test (SPT) sampler. The SPT sampler obtains disturbed samples and was driven into the soil using a 140- pound hammer fret-falling 30 inches. The number of blows required to drive the sampler the last 12 inches is recorded on the boring logs. Materials encountered in the exploration borings were studied and classified in the field by a geotechnical engineer from our firm. All exploration borings were sealed with bentonite and cement immediately after examination and logging. Selected samples were then transported to our laboratory for further visual classification and testing, as necessary. The boring logs have been attached to this report as an Appendix. 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field explorations accomplished for this study, visual reconnaissance of the site, and review of applicable geologic and geotechnical literature. As shown on the exploration logs, the site soil profile generally consists of a relatively thick pavemLat section overlying soft/loose silty fill overlying medium dense to very dense Vashon till. The site soil types are consistent with those mapped on the Distribution and Description of the Geologic Units in the Everett Quadrangle, Washington, Minard, 1981. The following section presents more detailed subsurface information organized from the shallowest (youngest) to the deepest (oldest) sediment types. 4.1 Stratigraphy Fill Fill at this site was observed to depths of between 1 and 6 feet below existing site grades. The site appeared to have been cut to grade along the western property boundary and contains fill along the eastern property boundary. Fill depths along the eastern property boundary generally ranged between 3 and u feet de:p (exploration borings EB-1, EB-4, EB-6, and EB- 8). Fill depths within the central portion of the property generally ranged between about 1 to 4 feet (exploration borings EB-7, EB-9, EB-10, EB-11, E13-12, and E13-13). Fill depths along the western property boundary were generally less than a foot (exploration borings E13-2, EB- 3, and EB-5). The fill consisted of loose to medium dense, fine to medium sand containing variable amounts of silt, gravel, and organic matter. Exploration borings EB-1, EB-9, and EB-11 encountered highly organic and/or peat within about 5 feet of existing grades. Existing fill material, including aggregate base below pavements and aggregate surfacing in existing parking lot areas, should be expected to be encountered across the property. We recommend November 28, 2005 ASSOCIA7'IiD EARTH SCIENCES, INC r.Gnd-KF01601e2.Pm/Ms 209rta2 KVWP Page 3