Laserfiche WebLink
• Table 3~1: CRSP Parameter Ranges for Representative Site Conditions <br />Site Condition Tangential <br />Coefficient Restitution <br />Coefficient <br /> Min Ave Max Min Ave Max <br />Sandstone cliff face .83 .85 .87 .33 .35 .37 <br />Road pavement .83 .85 .87 .33 .35 .37 <br />Talus covered upper foreslope 82 .835 .85 .30 .315 .33 <br />Thin colluvium overlying marine shales on <br />upper foreslope 80 .835 .85 .30 .315 .33 <br />Colluvium covered lowered foreslope 78 .805 .83 .28 .29 .30 <br />• The foreslopes have minimal surface roughness compared to the dimensions of the <br />blocks analysed. Under these circumstances the irregularity of the block becomes a <br />controlling factor, and Pfeiffer and Bowen suggest the effective roughness is then <br />equivalent to 25% to 50% of the block diameter. <br />A large number of runs were carried out for each slope using worst case, average, and <br />best case slope parameters, and effective roughness values in the range 25% to 50% of <br />block diameter. These runs demonstrated sensitivity to effective roughness but relative <br />insensitivity to slope parameters in the ranges investigated. Plots of predicated stopping <br />distances against observed stopping distances for various block sizes indicate that an <br />effective roughness of about 33% of diameter is appropriate for the design block size. <br />Effective roughness appears to increase slightly as block size decreases, presumably in <br />response to the increasing influence of slope roughness and vegetation at these smaller <br />block sizes. However, a comprehensive investigation of this relationship was not <br />• undertaken. <br />ie <br />