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<br />• drainageways. Site specific investigations will be required to confirm strength <br />properties of the foundation soils. <br />A pseudo-static earthquake analysis is appropriate since liquifaction of <br />foundation soils is not considered likely. Pseudo-static horizontal coefficients of <br />0.05, 0.10 and 0.15 were evaluated. The calculated factor of safety for total stress <br />conditions and a 0.05 coefficient exceeds 1.3. With the 0.15 coefficient a factor of <br />safety over 1.0 is calculated. We believe the hazard classification associated with <br />the fills (remote location, lack of population or public improvement) indicates these <br />results are satisfactory. <br />To summarize, static analysis shows adequate factors of safety (> 1.5) for the <br />normal strengths evaluated. Low friction angles in the native soils (less than 15 <br />degrees) are not anticipated, but the strength properties of the clay should be <br />evaluated during site specific investigations. Buildup of water in the fills results in <br />potential slumping near the toe, indicating drainage is required. Pseudo-static <br />• analysis indicates satisfactory conditions (F.S > 1.3). <br />DESIGN AND CONSTRUCTION RECOMMENDATIONS <br />Following are initial recommendations for geotechnical related design and <br />construction aspects of the spoil fills. Since spoil has not been generated, the <br />recommendations will require confirmation or revision when spoil properties have <br />been evaluated. <br />Fill Configuration <br />The proposed fill face slope, 2.5:1 (H:V) slopes with 20-foot wide benches at <br />40-foot vertical spacing results in an average overall slope on the order of 3:1 (H:V). <br />Our analysis indicates the configuration produces a fill with satisfactory stability. <br />Variations in the face configuration (if desired) should be possible. We do not <br />• recommend steepening of the face. However, if construction results in one or more <br />LORENCITO COAL COMPANY <br />cTLR zs,zs~ 10 <br />