10105 19TH AVE SE Geotech Report 2018-01-02 MF Import

r � r • GeotechnicalEngineering Evaluation Everett Veterinary Clinic February 2i,2002 � NGA File No. 342902 Page 6 We recommend that the underground concrete vauit discovered during our field reconnaissance be � removed, and all loose soil or debris found in the vault excavation be removed. Firm native soils should I - be exposed in the excavation,and the excavation should be filled with rock spalis �r structural fill. Underground fuel storage tenks may exist on the site. If any underground fue) storage tanks are Iencountenzd during development, an environmental consulta it should be retained to provide recommendations for tank removal and site cleanup. The resulting excavation should be treated as Idescribed above for the existing concrete vault. IThe soils likel,y to be exposed during construc[ion are highly moisture-sensitive and will disturb easily when wet. We recommend that construction take place during the drier summer months. However, if construction takes place during the wet season,additional expenses and delays should be expected due to �. the we� conditions. Additional expenses could include the export oS on-site soil, the impoK of clean, � granular soi? for fill,and the need to piace a blanket of rock spalls in construction access a�eas. Erosion Control IThe on-site soils have a slight erosion potentiul,depending on how the site is graded and water is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed Iduring construction should be protected fmm erosion. Mcasures taken may include diverting surface water awuy from the stripped areas. ��it fences or straw bules should be erected to prevent muddy water � from leuving the site. Dismrbed areas should be repinnted with vegetation at the end of conswction. The vegetation should be maintained until established. The erosion potential of areas not stripped of vegetation should be minimal. Site Preparation and Grading The first step of site preparation should be to strip the ropsoil and any loose soils to expose medium dsnse or better native soils in building and pavemen� areas. The stripped materiul should be removed from the Isite or stockpiled for luter use as landscaping fill. The exposed building and pavement subgrades should be comp•rcted to u non-yielding condition using a heavy vibrntory roller. Areas obyrved to pump or weave during compaction should be overexcavated and replaced with structural fili. If wat conditions are encountered, compacting the subgrade may only disturb the native materinl. In this case, altemative site Istripping and grading techniques might be necessary. This could include using a large excavata NELSON GEOTECHNICAL ASSOC/ATES, INC. v r