On Stability of a Slope with Bedrock Using the Upper Bound Limit Analysis

The potential failure modes and stability of a slope with bedrock was investigated systematically based on the upper bound limit analysis in this paper. The effect of interface between bedrock and soil on the slope stability was discussed in detail. The equations for calculating safety factors for three possible failure modes of the slope with bedrock due to gravity were derived. The most dangerous failure mode of the slope was determined using a program to optimize the solution to the stability equation for the slope. Finally, the effects of the inclination angle along the interface, the controlling angle of the interface position, the slope angle, and the interface strength parameters on the failure mode and safety factor were examined quantitatively. The results show that the relative position of the bedrock-soil interface and the empty surface of the slope is an important factor affecting the stability of the slope. Regarding to global failure along the interface between bedrock and soil (Mode 1 in this paper), the safety factor decreases at first and then increases as the inclination angle at the upper part of the interface increases. The shear strength parameters along the interface have a significant influence on the failure mode and safety factor.