Rock slope stability assessment under natural seismic actions using pseudo-static analysis

Abstract

Usually, rock slope stability studies do not incorporate the dynamic loading conditions associated with natural seismic activity into their analysis. In this context, the objective of this study is to utilize probabilistic maps of natural seismic risk to calculate safety factors through the equilibrium method, considering both the static and pseudo-static state of a slope. The methodology employed involved the acquisition of slope geometry data in situ, the mapping of the orientation of the geological structures, and the determination of the properties and parameters required for the stability analysis. Furthermore, the seismic risk maps and the recommended step-by-step calculation of the seismic coefficient were collated. The results indicate that the slope is stable in static condition in relation to the discontinuous planar surface. The probability of exceedance of 2% yielded the greatest reduction in safety factor in relation to the static condition when applying seismic force to the block mass on the discontinuous planar surface. This reduction was 43% compared to the other probabilities. In all three pseudo-static seismic loading conditions, the safety factor remained above one, indicating that the slope remained stable. It can be demonstrated that seismic forces exert a significant influence on the mobilization of shear stress and the reduction of resistive shear stress in rock slopes, ultimately leading to a decline in the safety factor.