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Subsurface Exploration,Geologic Hazards,and <br /> Former Brien Ford Preliminary Geotechnical Engineering Report <br /> Everett, Washington Project and Site Conditions <br /> excavation to remove contaminated soils. The maximum excavation depth will be on the order <br /> of 18 feet below the existing surface and the extent of the planned excavation will include the <br /> commercial sales building footprint, approximately half of the total building footprint, and the <br /> adjacent paved area to the south. After remediation is completed the excavation will be <br /> backfilled with structural fill and covered with a crushed rock base course and new asphalt will <br /> be placed. <br /> We understand the commercial sales building was added on to the south end of the service <br /> intake building. The interior wall that separates the service intake side from the commercial <br /> sales side will remain and will be adjacent to the planned excavation. We anticipate that the <br /> planned excavation will undermine the supporting soil prism of the foundation for this wall. In <br /> addition,the south end of the excavation will undermine the supporting soil prism for the north <br /> end foundation of the detail shop. Underpinning is currently proposed to temporarily support <br /> these foundations during the planned excavation. <br /> 3.0 SUBSURFACE EXPLORATION <br /> The subsurface exploration for this study was completed on April 28, 2017. The exploration <br /> drilling was performed by Cascade Drilling, Inc., of Woodinville, Washington, working under <br /> subcontract to Associated Earth Sciences, Inc. (AESI). The conclusions and recommendations <br /> presented in this report are based on the single exploration completed for this study. We also <br /> relied on previously completed subsurface exploration data related to our previously <br /> completed reports, referenced above. The location and depth of the exploration completed for <br /> this study was completed within site and budget constraints. <br /> 3.1 Exploration Boring <br /> The exploration boring completed for this study was achieved by advancing hollow-stem auger <br /> tools with a trailer-mounted drill rig. During the drilling process, samples were obtained at <br /> 5-foot-depth intervals. The exploration boring was continuously observed and logged by a <br /> representative from our firm. The exploration log presented in the Appendix is based on the <br /> field log, drilling action, and inspection of the samples secured. The approximate location of <br /> the exploration is shown on the "Site and Exploration Plan," Figure 2. <br /> Disturbed, but representative samples were obtained by using the Standard Penetration Test <br /> (SPT) procedure in accordance with American Society for Testing and Materials (ASTM) D-1586. <br /> This test and sampling method consists of driving a standard 2-inch, outside-diameter, <br /> split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a <br /> distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the <br /> number of blows required to drive the sampler the final 12 inches is known as the Standard <br /> Penetration Resistance ("N") or blow count. If a total of 50 is recorded within one 6-inch <br /> interval, the blow count is recorded as the number of blows for the corresponding number of <br /> May 16,2017 ASSOCIATED EARTH SCIENCES,INC. <br /> AWR/Id-160594V003-2-Projects\20160594\KV\WP Page 2 <br />