Comparison of Strength Reduction Method for Slope Stability Analysis Based on ABAQUS FEM and FLAC<sup>3D</sup> FDM

Strength reduction method is widely used in the slope stability analysis. However, it is short of unified instability evaluation standard at present. And the different numerical calculation methods also influence the safety factor of strength reduction method. Taking a typical slope in this paper, the same model meshes are established in ABAQUS FEM and FLAC 3D FDM by using the self-compiled model transformation program ABAQUS-FLAC 3D . Then the same elastic-plastic constitutive and yield criterion are both employed in ABAQUS FEM and FLAC 3D FDM. The safety factors obtained from the two numerical calculation methods are compared, and the results are also compared with that of Spencer limit equilibrium method. It is observed the safety factors calculated by ABAQUS FEM are slightly higher than that of FLAC 3D FDM for the same instability evaluation standards. Moreover, the safety factors obtained from the run-through of plastic zone and the saltation of the displacement at characteristic point are much closer to that of Spencer limit equilibrium method. Hence the combination of the run-through of plastic zone and the saltation of the displacement at characteristic point as the slope instability evaluation standard is suggested in this paper. Meanwhile, the correctness of self-compiled improved strength reduction method is verified by comparing with the result of FLAC 3D built-in strength reduction method.