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! Prcliminary Gcotcchnical Lettcr <br /> Landslidc Evaluation and Repair <br /> I 4703 Glenhavcn Drivc <br /> H��erclt, Washington <br /> ['cbniary I, 2007 <br /> I NGA P'ilc No. 75570G <br /> Pagc 4 <br /> 9. Document thc results of our explorations, findings, condusiuns, and reconmiendations in <br /> � a writtcn gcotechnical cnginccring rcport. <br /> ISI7'E CONUI'I'IONS <br /> Surface Condilions � <br /> ( The residence and driveway arc located on a north trendina ridge. The rcsidence is located on a Icvel pad <br /> at the top of thc ridge with a steep east-facing slope descending to a drainaee r:rvine. and a westdacing <br /> Islope descending to Glenhaven Drive. The driveway traverses the west-facing slope from Glenhaven <br /> drivc on the south up to thc residcncc to thc north. Wc unJcrstand that landscaping work was donc on <br /> � the upper portion of the slope adjacent to thc residence in 2006. The major portion of the landslide <br /> t <br /> occurred on thc moderate to steep west-facing slope below the western side of the rcsidence and <br /> Idriveway.�bove Glcnhaven Drive. <br /> � We observed veriical displacement in seil adjacent to the concrete portion of the dri��eway, but this <br /> scction iias bcen dctcrmined lo bc out of thc scopc of thc planned slope repairs. During our visits to the <br /> � sitc, wc have also noted cracks in the concrete pavement. <br /> The upper portion of the IanJslide estends Gom under the wctitern portion of the entire concrete portion <br /> I of the driveway along a patio and landscaping area, to within approximatcly five fcet west of thc <br /> � <br /> residencc lo fonn a ocnerally arcuate scarp :�io„� �i,� �on or ei,� ,rd�. s�io�� a,� ��.�rn ,��� „o«� areas o( <br /> tcnsion cracl:s, slumps, and lateral movemcnts which rou,hly follow the arcuate shape of the upper scarp. <br /> Thc site i� rclatively level ncar Ihc residence, and morc moderatcly sloping within the obser��ed landslidc <br /> � area. Thc slopes become stecp further to the wcst above thc sidewalk along the eastern edge of I <br /> ! Glcnhavcn Drivc. Pmfilcs of thc ���cstdacing are shown Cross-scctions r\-r�'. 13-4', and GC' in Fi�ures <br /> 3. 4. and S, respccti��cly. <br /> tiubsm•facc Condilions <br /> Gcology: Thc gcologic wiits For this sitc are shown on thc Geolo i� c ��I:�p of Uie Evcrctt 7.S-Minutc <br /> Quadranele. Sno�iomish Countv, Washineton. by James P. Diinard (USGS 1935). The site is map�cd as <br /> glacial lill (Qet) and advance ouhvash (Qva). The till is described :�s a non-sorted mirture of silt, s:md, <br /> � <br /> I NELSON GEOTECHN/CAL ASSOCIATES, INC. <br /> S <br /> I <br />