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Limited Geotechnical Engineering Study <br /> View Ridge Elementary School Portable Classroom Installation <br /> Everett, Washington and Downspout Infiltration Feasibility <br /> Laboratory Testing <br /> Three laboratory grain-size analyses were performed on selected samples collected from the <br /> explorations. The grain-size distribution test results are included in Appendix B, and are <br /> summarized in Table 1, below. <br /> Table 1 <br /> Grain-Size Distribution Summary <br /> Silt Content by <br /> Sample Depth Weight(Measured USDA Soil <br /> Exploration (feet) USCS Description on#200 Sieve) _ Classification <br /> EB-8 5 Sand, Some Silt,Trace Gravel 8.0 Sand <br /> EB-10* 5 Silty Sand 20.5 Loamy Sand- <br /> Sandy Loam <br /> EB-10 7.5 Sand, Some Silt 7.5 Sand <br /> USCS=Unified Soil Classification System <br /> USDA=United States Department of Agriculture <br /> *Silty interbed isolated and tested separately <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> Our explorations completed in the location of the proposed portable classrooms encountered <br /> Vashon advance outwash underlying approximately 3 to 4 feet of medium dense existing fill soils. <br /> We recommend that new foundation pads for the portable classroom buildings are supported by <br /> either the very Vashon advance outwash, medium dense existing fill,or new structural fill placed <br /> over these materials. We have provided geotechnical recommendations for general site <br /> preparation, fill placement, shallow foundation design, and infiltration in the following sections. <br /> Site Preparation <br /> Site preparation of the planned portable building pad area should include removal of all grass, <br /> topsoil, and any other deleterious materials and the remaining roots grubbed. Areas where loose <br /> surficial soils exist due to grubbing operations should be considered as fill to the depth of <br /> disturbance and treated as subsequently recommended for structural fill placement. Any loose <br /> existing fill soils below footing areas should be recompacted to a firm and unyielding condition <br /> prior to the placement of structural fill or shallow foundations. Recommendations for structural <br /> fill are provided in the "Structural Fill" section of this letter-report. The finished building pads <br /> should be compacted to a firm and unyielding condition prior to the placement of the gravel <br /> working surface and the new portable building foundations. <br /> July 12,2023 ASSOCIATED EARTH SCIENCES,INC. <br /> BCY/Id-20100255E004-002 Page 6 <br />