Rock Slope Stability Modeling

Step-path slope failures in jointed bedrock are analyzed using the PCSTABL slope stability computer program. The model simulates bedrock as anistropic material with variable discontinuity lengths. Discontinuity lengths are varied by adjusting the number of boxes used in the BLOCK search routine. Bedrock discontinuity information is based on visual examination of rock cores and acoustic televiewer data. Anistropic strength parameters are obtained from direct shear testing of rock samples. Results provide an understanding of how slope factor of safety varies with slope direction and discontinuity length. The analysis methods are applied to a proposed 400-foot deep quarry in Central California. Slope stability evaluation is especially important in this case because a steep slope is desired for improved production, but the pit is located close to a highway and a canal.