Study of slope instability on the Bhaderwah–Bani Highway, Jammu and Kashmir, India

Abstract

Northwest Himalaya has witnessed lot of mass movements during the Quaternary period which have led to palaeoenvironmental degradation and deposition of erratic size sediments. These sediments have developed as fossil slides along the mountain slopes. In last few decades, the frequency of landslides has increased due to various factors such as complex geology, geotechnical properties of the rocks and anthropogenic activities. The investigation of rock slopes require geo–engineering evaluation to assess the instability of critical slopes leading to landslides particularly in the Himalayan region, where rocks are highly folded, faulted, jointed and weathered. In the present study, a total of 15 rock slopes have been selected for rapid assessment of instability condition using rock mass rating basic (RMRb), slope mass rating (SMR) and kinematics analysis techniques along Bhaderwah–Bani Highway in Jammu and Kashmir. Field surveys were conducted regarding required input data collection followed by laboratory works. The results of RMRb show two classes of rock mass, i.e., Class II–Good (86.58%) and Class III–Fair (13.42%). The SMR index classify rock slopes into different stability class results, which infers completely unstable (L4 and L14), unstable (L1, L2, L3, L8, L9, L11, L12 and L13), partially stable (L5, L6 and L7) and stable (L10 and L15) categories. The final output of kinematic analysis verify different modes of structurally controlled slope failures i.e., planar (30.72%), wedge (57.6%) and toppling (11.52%), representing all 15 sites in the study area.