Seismic stability analysis and charts of a 3D rock slope in Hoek-Brown media

Earthquakes act as a dominant trigger for failure of slopes in seismic active regions. In this study, a seismic stability analysis of a three-dimensional (3D) rock slope in Hoek-Brown media is conducted based on the limit analysis method. The energy balance equation is derived by equating the external work rate by rock mass weight and seismic forces to the internal energy dissipation rate, and an optimization code is then programmed to capture the optimized factor of safety (FoS) of a 3D rock slope based on the strength reduction technique. The validity of the equivalent Mohr-Coulomb parameters method and generalized tangent technique in conjunction with the limit analysis method to estimate FoS of a 3D rock slope is investigated. Subsequently, a quasi-static method is used to explore the effect of seismic forces on stability of a 3D rock slope. The results of the parametric analysis indicate that the seismic force exhibits significant negative effects on the stability of a 3D slope and that a significant difference exists between a 3D FoS solution and a solution obtained under two-dimensional (2D) plane strain. A stability chart analysis is performed to produce a set of seismic stability charts for preliminary design purposes. Finally, a case study is performed to apply stability charts in practical situations.