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Morrison Knudsen Corporation <br />• October 10, 1996 <br />Page 2 <br />• <br />To evaluate the strength parameters of the soil unconsolidated-undrained (U-U) triaxial tests <br />were conducted on three remolded specimens and one undisturbed sample, all from Boring 24. <br />Two of the remolded samples were compacted to approximately 85 % of two different modified <br />Proctor densities. The thud remolded sample was compacted to 90% of the higher modified <br />Proctor density to determine if the additional compaction resuited insignificant strength increase. <br />The samples were remolded near the optimum moisture content. Reference Figs. 4 through 7 <br />for the U-U triaxial shear results and Figs. 8 and 9 for the modified Proctor results. Results <br />from the previous study were also considered when determining the strength parameters for use <br />in the stability analysis. The following tabulates the U-U test results. <br />Sample Location Percent Compaction <br />(%) Angle of Internal <br />Friction Cohesion <br />(psf) <br />B-24 at 0-20 feet 85 32.5 2,200 <br />B-24 at 20-40 feet 85 28 1,600 <br />B-24 at 20-40 feet 90 30 2,900 <br />B-24 at 19 feet Undisturbed 36 4,100 <br />Slope Stability Analysis: The stability of the reclaimed slopes is dependent upon then ability <br />to resist shear stresses. These shear stresses are generated from internal body forces created by <br />the weight of slope itself. The sections described above were subjected to stability analyses <br />using current state-of-the-practice methods, Tire method deemed appropriate to analyze the <br />slopes was a conventional circular stability analysis. The computer program Geoslope 4.0 was <br />used, and is based on the program STABLE3 which was developed at Purdue University. The <br />following soil parameters were used in the program. <br />Soil Type Wet Density (pcf) Angle of Internal Cohesion (psf) <br /> Friction <br />Native, Undisturbed 125 0 4,000 <br />Material <br />Recompacted Fill 130 0 2,000 <br />Also included in the analysis was a phreatic surface located at a depth of 50 feet below the <br />ground surface. This was generally considered to be conservative since ground water was <br />• encounterrrd in only 3 of the borings. The above described conditions resulted in Safety Factors <br />