10632 7TH AVE SE Geotech Report 2025-07-28

I June 6,2008 Serenity Meadows IIAA Job No. 8A017 Page 9 the building pads. The exposed ground should be compacted to a non-yielding state with a vibratory roller compactor and proof-rolled with a fully loaded dump truck or water truck. During construction, storm runoff and groundwater seepage, if any, should be intercepted with ditches or interceptor trench drains,as required,and conveyed into temporary storage and settling ponds to rinimi7e soil erosion and to facilitate site grading work. Only clean, clear water in the settling pond may be released onto the adjacent wetland buffer zone. The onsite surficial soils contain a high percentage of fines and are sensitive to moisture. A layer of clean, 2-to-6-inch rock spalls should be placed over excavated areas and areas of frequent traffic, as required, to protect the subgrade soils from disturbance by construction traffic. Silt fences should be erected along the downslope boundaries of the site to prevent sediment being transported onto adjoining properties,streets or the wetland. The bottom of silt fence filter fabric should be anchored in a trench filled with gravel. EXCAVATION AND FILL SLOPES Under no circumstance should excavation slopes be greater than the limits specified by local, state and federal safety regulations if workers have to perform construction work in excavated areas. Unsupported temporary cuts greater than 4 feet deep should be no steeper than 1H:1V in surficial fill,relic topsoil or medium-dense weathered soils, and no steeper than 3/4H:1 V in the medium-dense to dense advance outwash soils, and may be vertical in the very-dense fresh till ' soils if the overall depth of excavation does not exceed 12 feet. Permanent cut banks should be no steeper than 2-1/4H:1V in fill and relic topsoil, no steeper than 2H:1V in weathered soils, no steeper than 1-3/4H:1 V in fresh advance outwash soils, and no steeper than 1-1/2H:1 V in fresh till soils. The soil units and the stability of cut slopes should be verified by a geotechnical engineer during excavation. 1 LW & ASSOCIATES, INC.