9001 AIRPORT RD Geotech Report 2018-01-02 MF Import

i � SuLsurface Ezpforatian, Geologic Hazard, and Preliminary Crtoteduucal Engu�en^g Report Sno-lsle Skil(s Center Addition Pre(imina Desi Recommendat�ons EvereK, W¢thin ton � III. PRELIMINARY DFSIGN RECOMMENDATIONS I 8A INTRODUCTION I It is our opinion chat from a geotechnical stagdpoint the site is suitable for the proposed improvements provided that the recommendations contained herein aze properly followed. htedium dense ro very dense lodgement till was encountered at relatively shatlo^� depths in our explorations on the site, and conventional spread footings may bc used for support of the proposed new buildings. Some overexcavation and replacement of fill soils should�or aceess if it is encountered below building foundations, floor slab azeas, or new parking :ueas. Standazd pavement sections should perform well within the proposed new pazking and bus loading azeas with proper subgrade prepazation. The existing fill and lodgement till suils contain substantial quantities of silt, and during the wet winter and spring months, the contractor and school district should be prepazed to manage over-optimum moisture content (wet) soil and subgrade conditions. Construction should be timed to take advantage of dry weather, if possible. 9.0 SITE PREPARATION Site prepazation of azeas to be graded should �c�i�ei de e er ous m ter al�Addirionally demolition debris from existing strucmres, and any roo� �bbed Bas�d o� our the upper organic topsoil should be removed and the remaining g explorations, the majority of the topsoil 6ad been stripped as pazt of original grading activities. If topsoil is present, it is expected chat it wiil be between 6 and 12 inches thick. Areas where loose soils exist due to previous grading, filling, or grubbing operations should be considered as uncontrolled fill to the depth of disturbance and treated as subsequently recommended for sWctural fill p.'acement. Where existing, loose fill or natural sediments aze relatively free of organics and near their optimwn moisture content for compaction, they can be segregated for reuse as sWctural fill. Since the density of the soil is variahle, random sofr pockets may exist, and the depth and extent of stripping can best be determined in the field by the geotechnicai engineer or engineering geologist. q ] permanent Cut and Fill Slopes Permanent cut and structural fill slopes that are not intended to be expo� i to stancling water should be graded no steeper than 2H:1V (Horizontal:Verticalj. P:cmanent cu[ and structaral fiil siopes that will be exposed to standing water should be inclined at 3H:IV or flatter. Slopes should be hydroseeded, landscaped, or otherwise protected as soon as possible aRer grading. Cut slopes in natural soils that must be steeper ihan 2A:1V should be protected by a rcekery or ASSOCIATED EdRTH SC/E��S,INC. �w1e��, Zppg Page 10 Fr,�m-�o5oiri,+s-r,qrm�musatt3�wP