Safety Analysis of Half-filling Half-digging Subgrade Slope

摘要

To study the stability of large amount of half-filling & half-digging subgrade slope in mountain area, the paper separately used shear strength reduction method by FEM (FEM-SSR) and slice method based on limit equilibrium theory (Bishop, Spencer, Morgenstern & Price) from aspects as nature of filling material, nature of bedrock, geometry of slope, treatment of filling slope toe to calculate the factor of safety and the critical slip failure surface. By comparing results got from two different series method, conclusions can be got as follow: Factor of safety calculated by two different series method fits well, the biggest deviation not more than 4.5%; the critical failure surface fits well too. The safety nature of project not only related to the filling material character but also the bedrock character. If the bedrock is stiff, the stability of the subgrade slope mainly decided by the filling part, on the other hand critical slip failure surface may extend into limp bedrock. Improvement of the compaction degree can increase the factor of safety for slope stability obviously. The geometry of the filling slope affects the slope stability apparently. The stability of filling slope can be improved obviously by build a rigid retaining wall at the toe of filling slope.