Seismic Three-Dimensional Stability of Concave Slopes by Lower Bound Limit Analysis

This paper is devoted to present a method of three-dimensional stability analysis of concave slopes in plan view based on lower-bound theorem of the limit analysis approach in static and seismic cases. Slope stability problems are often analyzed two-dimensionally by conventional limit equilibrium method (LEM). Accuracy of LEM is often questioned due to the underlying assumptions that it makes, and at the same time, analyzing a 3D problem two-dimensionally may lead to significant differences in safety factors depending on the slope geometries. In this paper, the numerical linear finite element and the rigorous lower bound limit analysis method is used to produce some seismic stability dimensionless charts for three-dimensional (3D) homogeneous concave slopes. The charts can be used by practicing engineers as a convenient tool to estimate the stability for excavated or man-made slopes. The results obtained using this 3D method show that the stability of concave slopes increases as the relative curvature R/H and the relative width of slope decrease.