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

i- . . . Geotechnical Engineering Evaluation Everett Veterinary Clinic February 21,2002 � NGA File No. 342902 Page 7 equipped with wide tracks and a smooth bucket for site stripping. The exposed subgrade should be � protected from construction traffic and surface water should be diverted around prepared subgrade. IThe on-site soils likely to be exposed during construction are considered highly moisture-sensitive and I will disturb easily when wet. These soils become very difficult to compact when wet of optimum moisture content. This often results in extra excavation and the need for importing all-weather material for fill, which could signifcantly raise costs. We recommend that earthwork be conducted during the fdrier summer months, if possible. If earthwork is to be accomplished during wet weather, we recomtnend that a blanket of rock spalls be placed in the planned access roadway. The thickness of the spall 5lanket Ishould be based on soil conditions at the time the site is developed, and the performance under heavy equipment. We recammend using a minimam of a I-foot thickness of spalls in traffic areas for estimeting additional wet weather costs. I_ Temporary Excavations � Temporary excavation stability is a function of many factors, such as the type and consistency of soils, depth of the cut, surcharge londs adjacent to the excavation, �ength of time a cut remains open, and the � presence of sur(ace or ground water. [t is exceedingly difficult under these variable conditions to estimate a stable, temporary, cut-slope geometry. Therefore, it should be the responsibility of the contractor to Imain[ain safe slope configurutions, since the contractor is continuously at the job site,able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and ground water i conditions encountered. � This information is provided soley for the benefit of the owner and other design consultants and should Inot be construed to imply that Nelson Geotechnical Associates, Inc„ assumes responsibility for job site sufety. Job site safety is the•sole responsibility of the project contractor. For planning purposes, we recommend that temporary cuts in the topsoil und the weathered till soils be no steeper than 2H:1V (Horizontal:Vertic�p. Cuts in the dense unweathered till may stand at a O.SH:1V inclination. If ground wnter seepage is encountered, flatter inclinations may be necessary. We , recommend that cut slopes be protected from erosion. Measures taken may include covering cut slopes , '� with plastic sheeting and diverting surface runoff away from the rop of cut slopes. We do not recommend I � � I NELSON GEOTECHN/CAL ASSOC/ATES, INC. �