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PN: 50663GE <br />November 20, 2006 <br />Moisture content and dry density; the moisture content and in-situ dry density of some of the <br />soil samples were assessed in general accordance with ASTM D2216 <br />Atterberg Limits; the plastic limit, liquid limit and plasticity index of some of the soil samples <br />was determined in general accordance with ASTM D4318 <br />Direct Shear Strength tests; Direct shear strength tests were performed on select soil samples <br />to estimate the soil strength chazacteristics in general accordance with ASTM D3080. The angles <br />of internal friction (phi) and cohesion values used in our analysis aze presented under the slope <br />stability section of this report below. <br />5.0 SLOPE STABILITY ANALYSIS <br />Our study included observations of the topography and geomorphology of the project site and <br />adjacent areas. Slope cross sections of critical portions of the site were prepazed based on the <br />site observations and the available topographic maps. The azeas analyzed included unstable and <br />potentially unstable slopes and areas where critical components of the proposed access roadway <br />site will be located. <br />There are numerous methods and techniques available for slope stability analysis. Most <br />methods include an evaluation of; <br />• the strength of the soil materials within the slope, <br />• anisotropies within the slope materials, such as formational material bedding planes, and <br />anomalous soil contacts, <br />• the subsurface water and soil moisture conditions, and, <br />• the pre-constmction and post-construction geometry of the slope azeas where <br />development and construction is proposed. <br />The data developed during the analysis is condensed and used to estimate the forces within a <br />soil mass that tend to drive movement and the forces that tend to resist movement. The ratio of <br />resisting forces to driving forces is often referred to as the "theoretical slope factor of safety" <br />(FOS) which is a somewhat misleading term to describe this ratio. The ratio is not a tme factor <br />of safety, but is a useful mathematical characterization of the forces within a soil mass and the <br />associated stability condition of the slope being analyzed. <br />A ratio of less than one (1) indicates that the driving forces within a soil mass are greater than <br />the resisting forces; therefore movement of the slope is occurring. A ratio of one (1) indicates <br />TRAUTNER ~ <br />A DIVISION OF TttIGONH~ <br />