Definition and transformation of slope safety factor based on Drucker-Prager criterion

Slope stability analysis was carried out using strength reduction finite element method (FEM) based on the Drucker-Prager (D-P) criterion. The definition of slope stability safety factor based on the D-P criterion was proposed, and the safety factor conversion formula with different D-P yield criteria was deduced. The substitutive relationship of safety factor based on the D-P yield criterion and Mohr-Coulomb yield criterion was set up. Currently, the Mohr-Coulomb hexagon circumcircle D-P criterion was adopted in the ANSYS program. So, the safety factor using ANSYS with the Mohr-Coulomb hexagon circumcircle D-P criterion is calculated, thus the safety factor based on the D-P yield criterion (such as the Mohr-Coulomb matching D-P yield criterion under the plane strain condition) can be obtained using the deduced conversion formulae. Under the plane strain condition, the Mohr-Coulomb yield criterion in the ANSYS program without secondary programming development through equivalent substitution is adopted. A series of case studies indicate that the average error of safety factors between those obtained by strength reduction FEM based on plane strain Mohr-Coulomb matching D-P yield criterion and those by Spencer method is 1%-2%. The applicability of the proposed method was clearly exhibited.