Assessment of complex rock slope stability at Xiari, southwestern China

Detailed engineering geological studies and stability assessments were carried out on Xiari rock slope in southwestern China. Geomorphic analysis of digital elevation models, detailed structural field mapping and boreholes data indicate that the slope has a poor rock mass quality and complex deformation mechanism. The necessary rock mass parameters were determined by means of slope mass rating (SMR), geomechanic classification system (Q) and geological strength index (GSI). Slope stability analyses were performed by means of kinematic, limit equilibrium and numerical modeling techniques. Analyses results indicate that slope stability is mainly controlled by the discontinuities. The combination of discontinuities and topography makes the slope susceptible for a large landslide. The major potential mode of slope failure is planar failure. Planar failure has a higher probability in comparison to wedge failure, while wedge failure contributes towards a more severe hazard, like the landslide in part A of the study area. Numerical analysis results indicate a catastrophic landslide in the future, with a volume estimated to be more than 2.5 x 10(6) m(3).