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' The Simplified Bishop Method satisfies overall moment and vertical force <br />equilibrium of individual slices, but does not satisfy the moment equilibrium of <br />' individual slices or horizontal forces equilibrium. However, this method is widely <br />used, and has been shown to produce accurate results over a wide range of soil <br />conditions. <br />' C. Assumed Material Properties: <br />The engineering properties of the existing colluvium and landslide materials were <br />' obtained from the geotechnical investigations by Chen and Associates and Geo- <br />Hydro Consulting, Inc. <br />Properties for the backfill materials were based on those properties:of the existtng <br />materials, modified to account for the degree of compaction and saturation. It has <br />been assumed herein that the backfill materiel most likely to be used, will have <br />originally been part of those existing, natural materials. The effective stress <br />' parameters which have been used in these investigations are as follows. <br />Existing Materials <br />Friction angle 30.5 Degrees <br />Cohesion 300 PSF <br />Unsaturated unit weight 115 PCF <br />' Saturated unit weight 120 PCF <br />Backfill compacted to 85% of maximum density <br />Friction angle 30.5 Degrees <br />Cohesion 300 PSF <br />Unsaturated unit weight 111 PCF <br />Saturated unit weight 118 PCF <br />Backfill compacted to 95% of maximum density <br />Friction angle 33.0 Degrees <br />Cohesion 300 PSF <br />Unsaturated unit weight 124 PCF <br />Saturated unit weight 125 PCF <br />D. Reclamation Alternatives at a Cross Section at Access Road Station 60+83 <br />' Station 60+83 of the access road is a critical road cross section in that portion of <br />the road within the landslide area. A large cut at the portal road turnout has also <br />been considered and is discussed in the next section. Six possible variations or <br />alternatives for reclaiming the cross section at Access Road Station 60+83 were <br />analyzed. These cases are summarized in TABLE 1, below. <br /> <br /> <br />5 <br />