Engineering geological assessment of the Barwas landslide Himachal Pradesh

Slope failures are very common during the monsoon season in hilly terrains. The occurrence can be attributed to the interaction of various controlling factors, including geological structures, terrain morphology, hydrological processes, and human-induced activities. The instability and stability of a slope is controlled by various factors, including lithology, structural discontinuities, hydrological conditions, slope geometry, and the geotechnical properties of the materials involved. The study conducted for the Barwas slope along National Highway-707, where the dominant lithology, comprising calcareous shale and dolomite, is highly folded, faulted, and fractured. The study area is situated between 30° 35′ 24.67″ N and 77° 39′ 28.44″ E, within the Sirmour district, representing a geodynamically active terrain influenced by complex structural deformation. The Rock Mass classifications indicate the inherent instability of the slope. These geological factors, combined with anthropogenic activities such as mining and road-widening, have contributed to failure of slope. The factor of safety (FOS) from the pre failure analysis, is observed to ranges between 0.48 and 0.97, further emphasizing the susceptibility to failure. The study suggests that rainfall, seismic activity, and unregulated human interventions are potential triggers for future slope failures.