3D Stability Charts for Convex and Concave Slopes in Plan View with Homogeneous Soil Based on the Strength-Reduction Method

Abstract

The analysis of slope stability problems in engineering practice requires considerable attention for the three-dimensional (3D) effect of plan curvature of the slope. This paper quantifies this effect by a dimensionless parameter of the relative curvature radius of the slope (R/H) and proposes a set of 3D stability charts that can be used to estimate the factor of safety (FOS) of convex and concave slopes in plan view with homogeneous soil, extending those currently regularly used for 3D straight slope stability evaluations. To simplify the computational process, an alternative way to perform the FEM with the strength-reduction technique is used herein in the slope stability analysis. The strength-reduction analysis results in this paper together with results of other researchers were found to bracket the FOS to within ±5% or better and therefore can be used to benchmark the solutions of other methods. Changing the relative curvature radius of the slope (R/H) shows that concave slopes are more stable than straight slopes, but that convex slopes are less stable; moreover, the 3D effects are more significant in slopes with friction/cohesive soils with smaller values of R/H. Numerical 3D results are presented in the form of dimensionless graphs, which represent a convenient tool for practicing engineers to estimate the initial stability of excavated or artificial slopes.