Influence of Slip Surface Shape on 3D Slope Stability Analysis: Fid-Bau Portal

Influence of Slip Surface Shape on 3D Slope Stability Analysis

Fredlund, Murray D. / Gitirana, Gilson de F. N. / Ivkovic, Zenja / Lu, HaiHua

The analysis of the stability of slopes using the limit equilibrium method largely depends on the use of an adequate procedure for finding the position and shape of the critical slip surface. Critical slip surfaces have been traditionally determined using brute force techniques that rely on assumptions regarding the shape of the slip surface, thereby imposing considerable constraints. Several optimization methods have been proposed in the literature to improve the search procedure for critical slip surfaces. Unfortunately, most research involving optimization methods has been confined to two-dimensional analysis. This paper examines the use of an optimization technique to different slope stability problems in three dimensions. The presented results show that the procedure is capable of locating a lower minimum factor of safety when compared to conventional approaches, even if the initial arbitrary slip surface adopted for the optimization procedure is not close to the converged slip surface. It was also demonstrated that the optimization procedure is capable of identifying composite shapes produced by the presence of a weak layer. The shape of the critical slip surface obtained using the optimization procedure was shown to deviate from an ellipsoidal shape when conditions such as weak layers of material anisotropy are present.