Stability Analysis of Rock Slopes Reinforced by Passive Fully Grouted Bolts Using the Generalized Hoek-Brown Criterion

This work presents a stability analysis of reinforced rock slopes using the kinematic approach of limit analysis theory. The reinforcement system consists of several layers of passive fully grouted rock bolts, uniformly distributed along the height of the slope. The rock material considered herein is homogeneous and isotropic, whose strength properties are described by a modified Hoek-Brown failure criterion. Regarding passive bolts, they are modeled as bar-like inclusions that exhibit only a resistance to compression-traction forces. The stability analysis is carried out under the plane strain condition. To implement the kinematic approach, a rotational failure mechanism is adopted to derive rigorous lower bound estimates for the amount of reinforcement strength to prevent slope failure. In order to evaluate the accuracy of the proposed approach, the lower bound estimates are compared with the solutions obtained from the standard OptumG2 software which implements a finite element formulation of the static and kinematic approaches of limit analysis. The approach is then applied to carry out a series of numerical simulations by considering the case of a carbonate rock with well-developed crystal cleavage that is cut by many intersecting joints. The results of the simulations are used to investigate the effects of the horizontal seismic coefficient and the disturbance coefficient on the necessary reinforcement strength.