Stability analysis of anchored rock slopes against plane failure subjected to surcharge and seismic loads

The stability analysis of rock slopes has been a challenging task for engineers because the rock mass constituting the slope often has discontinuities in various forms, resulting in different types of slope failures. The plane failure is one of the rock slope failures observed in field situations when the discontinuity is in the form of joint planes. There are several parameters including surcharge and seismic loads that govern the stability of the rock slope against plane failure in field projects. The limit equilibrium approach for the estimation of the factor of safety of the rock slope against plane failure has been well accepted by the engineers in the past. Very recently, attempts have been made to present analytical expressions for the factor of safety of the of the rock slopes against plane failure, which are not in a generalised form because they do incorporate most field parameters. Therefore, in the present work, the analytical expression for the factor of safety of a single-directional anchored rock slope (SDARS) is derived, along with a discussion of its special cases in view of different practical situations. Parametric studies and design charts for the stability of the SDARS are presented, and an illustrative example is included to explain the calculation steps for the factor of safety. In order to investigate the effect of multi-directional rock anchors on the factor of safety, an analytical expression for a multi-directional anchored rock slope (MDARS) is also presented