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- 11 - <br />~~ <br />C~ <br />Literature published by the U.S. Bureau of Reclamation and our <br />experience with similar embanlanents indicate that dams of similar <br />material and slopes have factors of safety exceeding those suggested <br />for earth dam cronstruction. Results of our laboratory tests were <br />wmpared with those given by the U.S.B. R. as average properties of <br />soils. The comparison is as follows: <br />Chen and Associates USER USBR <br />Test Results Soil Group CH Soil Group CL <br />Maximum Dry <br />Density (pcf) 99.4 94+1 108 + 1 <br />Optimum <br />Moisture 22.5 25.5 + 1.2 17.3 + 0.3 <br />Content (~) <br />Cohesion (psi) 9.0 Saturated 1.6 + 0.9 1.9 + 0.3 <br />Optimum 10,5 + 4.3 12.6 + 1.5 <br />Tan N 0.27 0,35 + 0.09 0.54 + 0.04 <br />Examination of these test results, Atterberg limits and minus <br />200 contents indicates the soil generally ranges between the CL and CH <br />soil groups. Ebr calculation purposes, we have assumed the following <br />criteria: <br />(1) Maximum embanlanent height = 10 feet <br />(2) Downstream face = 2.5:1 (horizontal to vertical) slope <br />(3) Upstream face = 3:1 (horizontal to vertical) slope <br />(4) Unit weight of soil = 99,4 pcf <br />(5) Tangent a = 0.27 <br />(6) Cohesion = 1.6 psi (230 psf) <br />• <br />