10630 EVERGREEN WAY BASE FILE 2016-01-01 MF Import

Geotechnical Engineering Report Proposed New Storm Water Vault Northwest M�isubishi November 18, 2002 CG Pile No. 139i Page 3 SITE CONDITIONS Surface Conditions The south�aest comer of the dealership is a "U" shapcd grass-lincd swale used for stortn water treatmcnt. Therc is a north to south trending 3- to 4-foot-high rockcry on the east sidc of thc swale,which runs through approximatcly ihe centcr of the planned vault. A sccond north to south trending 3-foot-high rockery divides thc two halvcs of the "U" shaped swale �nd is locared along the west side of the planncd vault. The existing paved parking area is about l2 feet east of the edge of the planned vault excavation. Thcre arc liglit poles on concrcte column bases on the west side of the parking approximatcly 10 feet from the planned excavation. Wc do not know the depth of the column foundations. The existing manhole cover is at roughl�� rlevati�n Cr10.5 fect. Wc uscd this lid to detcrtnine the relative clevations of our exploratio�s. There is currently a singlc ro�� of 2-Coot-high ecolagy btocks along the ��cst property linc. Ezplorafions Subsurface conditions «cre explored at the site on No��ember 7, 2002, by excavating two test pits. The test pits were excavated to depths of 9.5 and 7.5 feet bclow the 6Tound surface. 1'he explorations were locatcd in thc ficld hy an enginecr from this firm who also examined the soils and geologic conditions encountcrcd, and maintained logs of the test pits. The approximate locations of the test pits are shown on the Sitc Plan in Figure 2. The soils were visually classifieu in general accordance with the Unificd Soil Classification System, a copy of which is presenled as Pigure 3. 'Chc logs of the test pits are presen�ed in Figure 4. The ground surface at Test Pit I was aLout G39 feet and thc ground surface was about 638 feet based on the existing manholc cover at 640.5 fcet. Subsurface Conditions Thc explorations both encountcred till �vith tracc organics. The fill was 7 feet deep in Test Pit l (down to about cle��ation G32 feet) and n-as G.5 feet decp in Test Pit 2 (down to aboat elevation Cornerstone Geotechnical, Inc. ��