Auxiliary slope reliability analysis using limit equilibrium method and finite element method

The limit equilibrium method (LEM) and the finite element method (FEM) are two commonly-used slope stability analysis methods. The LEM-based slope reliability analysis is computationally efficient based on the prescribed slip surfaces, while the FEM-based one tends to give more realistic reliability estimates. A new simulation-based reliability method, namely auxiliary slope reliability analysis method, is developed, which includes two major steps (preliminary and target reliability analyses) and makes use of advantages of both LEM and FEM to achieve efficient and consistent slope reliability analysis. A two-layered slope example considering spatial variability is illustrated using the proposed method. The results indicate that the proposed method gives reliability estimates consistent with those obtained by the Monte Carlo simulation or subset simulation based on FEM, and it also significantly reduces the computational efforts at small probability levels. This enhances the application of FEM-based reliability analysis in slope engineering practice. The information generated in the LEM-based reliability analysis can be properly incorporated into the FEM-based reliability analysis, through which a large amount of failure samples can be obtained and used for making slope remedy measures. In addition, the proposed method is very practicable for high-dimensional reliability problems, such as slope reliability problem considering spatial variability.