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the piezometric line used in the analysis and shown on Plate No. 1 <br />• is probably conservative. <br />The shear strength for the waste material was taken from the <br />triaxial testing described in the previous section. As previously <br />noted, the effective friction angle was 31.12 degrees, and the effec- <br />tive cohesion was 1.42 psi, equal to approximately 204.5 psf. It was <br />assumed that the waste material would have an average dry density of <br />around 80 pcf, and the in-place moist density was taken as about 92 <br />pcf, For the native alluvium overlying bedrock, an effective fric- <br />tion angle of 36 degrees with an effective cohesion of 200 psf was <br />assumed. This value corresponds with typical shear strength data <br />for similar materials, and is probably somewhat conservative. The <br />unit weight of the alluvium was taken as about 130 pcf. For the sand- <br /> stone and shale bedrock materials, an effective friction angle of 38 <br /> degrees and an effective cohesion of 1000 psf caas assumed. The unit <br />caeight was taken as about 150 pcf. <br />The computer model was set up as shown Plate No. 1 with vertical <br />and horizontal distances being represented by a right hand Cartesian <br />coordinate system. On Plate No. 1 the heavy line represents the con- <br />figuration of the proposed pile as shown on the drawings provided to <br />ROCKY MOUNTAIN GEOTECHNICAL. <br />SLOPE STABILITY ANALYSIS: <br />A slope stability analysis was performed on the mathematical <br />model described in the previous section. There are many methods for <br />slope stability analysis which are in common use. Generally, the <br />analysis will provide a means for calculating the forces tending to <br />cause failure, and the forces which resist failure. Once this is <br />