Stability analysis of rock cut slopes along the Minas road between Ichhari Dam and Minas Bridge, Tons valley, Garhwal Himalaya

Slope failures are common in Himalayan terrain. Highways become more vulnerable to slope failures due to road cutting and widening, expansion of towns and markets settled along the highway, erosion and toe cutting by large rivers and their tributaries etc. The present study incorporates detailed geological mapping and delineation of weak zones prone to slope failures along the Minas road between Ichhari Dam and Minas Bridge. Slope stability analysis of a number of slopes along the Minas road has been carried out. Study of joints was carried out at 63 locations along 40 km road section of study area. Slope Mass Rating (SMR) was calculated on a number of outcrops exposed along the road cut slope. Kinematic analysis by Markland's Method has been utilized to decipher the possible mode of failures and their directions. Considering the similarity in lithology and orientation of joints, the road section has been divided into ten sectors to identify the role of structural discontinuity in weakening of rocks and slope failures.