9702 19TH AVE SE Geotech Report 2024-03-28

Earth August 26, 2021 Earth Solutions NW I_I_c ES-7829.01 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Pacific Ridge — DRH, LLC 17921 Bothell-Everett Highway, Suite 100 Bothell, Washington 98012 Attention: Mr. Scott Borgeson Dear Mr. Borgeson: Earth Solutions NW, LLC (ESNW), is pleased to present this report titled "Geotechnical Engineering Study, Proposed Residential Development, Grayson Square, 9702 & 9620 — 19th Avenue Southeast, Everett, Washington". Based on the results of our investigation, construction of the proposed residential development is feasible from a geotechnical standpoint. Our field observations indicate the site soils consist primarily of loose to medium dense existing fill underlain by medium dense to very dense silty sand with gravel glacial till deposits, which extend to the maximum observed exploration depth of approximately 30.5 feet below the existing ground surface. The site is proposed to be developed with townhome building pads, access drives, and a stormwater detention vault. Mass grading activities will include cuts and fills of up to 18 feet and constructing Lock and Load retaining walls. New structural fill should be placed on competent soil. Given the condition of the existing fill on the site, remedial measures will be necessary where existing fill underlies new development. Such remedial measures will likely consist of reworking and compacting the existing fill and/or excavation and replacement with structural fill. If earthwork activities occur during wet weather, additional drainage measures, cement treatment of native soil, and/or the use of select fill material will likely be necessary. After completing earthwork activities in accordance with recommendations in this report, the proposed structures can be supported on conventional spread and continuous foundations bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. This report provides geotechnical analyses and recommendations for the proposed residential development. The opportunity to be of service to you is appreciated. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC -A tk_ S Adam Z. Shier L.G. Project Geologist 15365 N.E. 90th Street,Suite 100 0 Redmond,WA 98052 0 (425)449-4704 • FAX(425)449-4711