3606 W MUKILTEO BLVD 2016-01-01 MF Import

Gcotechnical I:nginccring Gvaluation Mukiltco Doulevard Devclopment Evcrctt, Washington March 31, 2003 NGA Pile No. 3GG503 1'agc 4 ouhvash. Fill materia! was encountcred in one of the explorations. Explorations: The subsurface conditions were e�plored at the site on March 19, 2003 by excavating clevcn tcst pits to depths of 4.2 to 14.2 feet below thc existing ground surface using a backhoe. The explor�tions were located in the field by nn NGA engincer who also examined the soils and geologic conditions encoimtcred and maint�incd logs of thc test pits. Thc approximatc locations of our cxplorations are sho��n on thc Sitc Plan in Figure 2. The soils wcrc visually classificd in general accordancc with the Unitied Soil Clnssification System, presented as Figure 3. The logs of our esplorations are presentcd as Figures 4 through 6. We present a brief summary of thc subsurface conditions in thc following paragraphs. For a morc dctailed description of the sitc soils, the Icst pit logs should bc rcvicwcd. Our subsurfacc explorations cncountcrcd a surficinl laycr of topsoil OA ro 2.1 fcct thick. Thc subsurfacc soils wcrc highly variablc, not only bchvicen diffcrcnt tcst pit Ircations but also in individuai explorations. '1'ypically, the tcst pits encountered scveral different layers of soil approximately cach layer was two to four fcct in thickness. The diffcrcnt soil types included: silty fine to medium sand with fine gravel, silt, silty finc to mcdium sand, silty fine sand, silty finc sand with occasional gravel pockets, silt with finc sand, silt with finc to medium sand, silty finc to coarse sand with fine gravcl, silty fine sand/sandy silt, finc sand, ntcdium to coarsc sand, silty fine ro conrse sand with gravel, and medium to coarsc sand with grnvel and cobtles. Nc have intcrprctcd thesc materials as glacial drift anJ rccessional ouhvash. In Tcst Pit 11, tlic topsoil �vas undcrlain by loosc silq� finc to mcdium sand, evaluatcd as fill, which c�tcnded to a dcpth of 2.8 fcct. A laycr of buricd topsoil, 0.2 fcct thick, was obscrvcd bclow thc fill soils. The matcrials �vc obscrvcd bcncath thc buricd topsoil �ecre gcncrally morc granular and Iess moismrc- scnsitive than thc soils cncountcrcd in the othcr c�plorations. These included: silty finc to medium sand, silty finc to coarsc sand with gravcl, medium to coarsc sand with gravcl and cobblcs, and finc sand. li}'drologic Conditions: Slight ground watcr sccpagc was cncountcrcd in Test Pits 2, 3, 4, 5, and 9. This secpage was encountercd abovc rclativcly impermcablc materials, and is interpreted to be perched ground watcr. Perchcd ground ��'ater occurs nhcn surtacc ��ater infiltratcs through more pernieable, ncarvsurface soils, NELSON GEOTECHN/CAL ASSOCIATES, INC.