3606 W MUKILTEO BLVD 2016-01-01 MF Import

Geotechnical Engineering Gvaluation Mukiltco I3oulcvard Devclopmcnt Evcrett, Washington March 31, 2003 NGA Pilc No. 36G503 Pagc 7 Thc on-sitc soils are rclativcly wet and contain substantial amoimts of silt. Thc on-site soils are considcrcd highly moisture-scnsitivc and will disturb easily when weL We recommcnd that earthwork takc pince during the drier summer months. I lowever, if construction takcs placc during the wet season, additional cxpenscs and dclays should be expected due to the wet conditions. Additional expenses wuld includc thc nced to export on-site soil, thc import of cican, granular soil for fill, thc necd to place a layer of rock spails in construction access areas, the need to protect exposed subgrades from conswction traftic and surfacc watcr, anJ dclays. Erosion Control The on-site soils have a modcrate erosion potential, dcpending on how the sitc is graded and watcr is allowed to concentratc. Best Management Practiccs (BMPs) should be uscd to control crosion. Arcas disturbed during constniction sliould be protected from crosion. Measures taken may include diverting surfacc watcr away from thc stripped areas. Silt fences or straw bales should be erected to prevent muddy �eatcr from Ieaving the sitc. Disturbcd arcas sl�ould bc replan[ed with vegetntion at thc end of construction. Thc vegetation should be maintained until established. Thc crosion potential of area; not strippcd of vcgetation should bc minimal. Site Preparation and Grading Thc first stcp of site preparation should bc to s'rip thc topsoil and any fill or loose soils to exposc mcdium densc or bcttcr nnti��e soils in building, pavemcnt, and sidewalk arens. The stripped material should bc removcd from the sitc or slockpilcd for latcr use as landscaping filL The e�poscd subgradcs should bc compactcd to a non-yiclding condition using a hca��y vibratoq� rollcr. Arcas obscrved to pump or wcavc dwing compaction sliould bc overexcavated and replaced with structuml fill. If wet conditions arc cncountcrcd, compncting thc subgradc may causc disturbmicc of thc nativc matcrial. In this case, altcrnativc sitc stripping and grading tcchniqucs might bc nccessary. This could includc using largc e�cnvators cquipped with ��ide tracks and smooth buckets for site stripping, and limiting construction traffic during sitc grading. G�posed subgrades should be protccted from constn�ction traffic and surfnce watcr should bc di�•crtcd around prcpared arcns. Thc on-sitc soils likcly to be e�posed during construction are considered exvemely moisture-sensitive and will disturb casily whcn �vcL Tlicsc soils are essentially impassible to compnct to swctural fill sn��r��o��s ��hcn �vct of optimum moisture contenc This mny result in cstn cxcavation and the nced NELSON GEOTECHNICAL ASSOCIA .TES, INC.