Determining the Critical Slip Surface of Three-Dimensional Soil Slopes from the Stress Fields Solved Using the Finite Element Method

Abstract

The slope stability problem is an important issue for the safety of human beings and structures. The stability analysis of the three-dimensional (3D) slope is essential to prevent landslides, but the most important and difficult problem is how to determine the 3D critical slip surface with the minimum factor of safety in earth slopes. Basing on the slope stress field with the finite element method, a stability analysis method is proposed to determine the critical slip surface and the corresponding safety factor of 3D soil slopes. Spherical and ellipsoidal slip surfaces are considered through the analysis. The moment equilibrium is used to compute the safety factor combined with the Mohr-Coulomb criteria and the limit equilibrium principle. Some assumptions are introduced to reduce the search range of center points and the radius of spheres or ellipsoids. The proposed method is validated by a classical 3D benchmark soil slope. Simulated results indicate that the safety factor of the benchmark slope is 2.14 using the spherical slip surface and 2.19 using the ellipsoidal slip surface, which is close to the results of previous methods. The simulated results indicate that the proposed method can be used for the stability analysis of a 3D soil slope.

3D Limit Equilibrium Stability Analysis of Concave and Convex Slopes Considering Kinematic Constraints

“…Cheng and Lau [11] adopted the simplified Bishop method and simplified Janbu method to study the influence of slope curvature on spherical damage of concave and convex slopes, and they concluded that compared with straight slope, the factor of safety (FS) of concave slopes and convex slopes are larger and smaller, respectively. Although these works predicted accurate enough FSs of concave and convex slopes, curved surfaces are necessary to be assumed for slip surfaces, such as cylindrical [12], spherical [13], and ellipsoidal [14]. More importantly, these postulated slip surfaces may not satisfy the flow law, thus predicting unrealistic FSs.…”