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Of these properties, an increase in friction angle and cohesion translates into a more stable <br /> slope. In contrast a decrease in unit weight results in a more stable slope. As can be seen the <br /> measured values of each of these tends to increase the stability of the waste bank slope and thus <br /> the original assumed values are indeed conservative. The safety factors for the new pile <br /> configuration will increase due to the effect of the more stable pile geometry (flatter surface <br /> slope) as well as due to the field measured soil parameters. For example, the stability analysis <br /> was redone for section 4 resulting in a factor of safety of 4.7. Results are shown on the attached <br /> worksheets. <br /> 4. Construction Densities <br /> State regulations require that waste material be placed in the bank and compacted to at least <br /> 90% of the maximum dry density. Soil sample taken from the drill hole were used in a Proctor <br /> Test to determine the maximum dry density and the optimum moisture content. The tests <br /> conformed to the required AASHTO T99-74 standard procedure. Results are; <br /> Maximum Dry Density = 91.0 pcf <br /> Optimum Moisture Content = 12.0% <br /> Four samples were tested to determine the field density of the existing waste bank. Of these <br /> two were reported by Lambert and Associates as, "may have experienced disturbance". The <br /> remaining two indicated compaction rates of 91% and 94% and thus conform to the <br /> requirements. <br /> 5. Drainage Features <br /> The Eastside drainage channel will be moved from its existing location, to the north against <br /> the natural hillslope as shown in figure 2. This channel will terminate at a junction with a buried <br /> pipe which is part of the drainage plan detailed in a separate Technical Revision. An earthen <br /> diversion structure will be constructed about 50 feet above section 4 to divert natural drainage <br /> into the relocated channel. As stated in TR1 (April 1991) an intercept ditch is required both at <br /> the top and bottom of the pile. The upper ditch will slope from the west end (section 1) to the <br /> east end (section 4) of the pile and will drain into the eastside channel above the diversion berm. <br /> The lower intercept ditch will slope from the east to the west and will be connected to the yard <br /> drainage system which terminates in the sedimentation ponds. <br />