Abstract: The generalized Hoek-Brown (HB) criterion has been widely applied to the computation and analysis of rock mass. However, the generalized HB criterion is a typical nonlinear failure criterion, so that it can’t be directly used in conjunction with shear strength reduction finite element method (SSRFEM) for the stability analysis of rock slopes. In response to this problem, the instantaneous linearization technique is investigated, in which for an arbitrary stress point, the instantaneous cohesion and internal friction angle corresponding to a tangent line with respect to the HB envelope can be obtained. Consequently, two instantaneous linearization strength reduction schemes are proposed: 1) Based on the stress field attained from the elasto-plastic analysis, the Mohr-Coulomb (MC) strength parameters of each stress point can be reduced, and the resulting approach is denoted as Point-IL-SSRFEM; 2) Since the strength parameters are required to be constant in each element for conventional finite element method, the attained instantaneous strength parameters for stress points in each element shall be averaged and then reduced, and the resulting approach is denoted as Element-IL-SSRFEM. Based on the calculation example of rock slope, the three-parameter strength reduction technique and the instantaneous linearization strength reduction technique are compared. The numerical results show that: compared to Element-IL-SSRFEM, the numerical accuracy and computational efficiency of Point-IL-SSRFEM are relatively high; Compared to the three-parameter strength reduction technique, the numerical accuracy of Point-IL-SSRFEM is higher and the computational performance of Point-IL-SSRFEM is more stable. Therefore, it is recommended to apply it to the stability analysis of rock slopes.

Key words: rock slopes, generalized Hoek-Brown criterion, instantaneous linearization, shear strength reduction, factor of safety