Stability analysis of road cut slope near Devprayag in Lesser Himalaya, India

The slope instability issues in Himalayan terrain is drastically increasing due to variety of anthropogenic activity and rapid urbanization. Road and highway networks in mountainous regions are the main source in remote parts of hilly terrain for the transportation as well as all sorts of socio-economic features. The study of slope stability in these hilly regions along the highways and roads are major concern, where slope instability caused transportation problems, death and injury of human, loss of their properties and also environmental degradation. Present article exposed the slope instability analysis for the two typical slopes along National Highway (NH-7), between Devprayag and Mulyagao in Uttarakhand, where the Highway goes up to the holy shrine of Kedarnath and Badrinath. The vulnerable slopes are numerically simulated using limit equilibrium method (LEM) and finite element method (FEM) for dry and saturated condition. The comparative analysis of factor of safety for LEM and FEM results show good correlation, i.e., 1.6-2.4% variance in dry condition and in saturated condition the LEM and FEM results show 11-13% variance. The finite element simulation has also assessed the principal stresses and displacement vector, which gives more understanding to identify and reveal the slope stability issues in analogous morphology. The result shows that both the slopes are in critical condition and prone to failure in rainy season due to exertion of water in intensely fractured rocks.