Engineering Geological Investigation and Slope Stability Analysis for Landslide Hazard Assessment in Indian Himalayas

The Indian Himalaya is very prone to landslides due to its complex geology and tectonic set-up along with high intensity rainfall and aggravated slope conditions as a result of anthropogenic activities. Landslide hazard assessment is very essential before any hill development construction activity begins. Engineering geological investigation forms the primary basis for any slope stability assessment leading to plan for any construction so that landslide occurrences are minimized. Engineering geological data for rock slope stability assessment can be very easily collected from the field. These data can be used for rock mass characterization and classification such as Geological Strength Index (GSI), Rock Mass Rating (RMR) and Slope Mass Rating (SMR). The paper describes these rock mass classification techniques and presents some field examples. The paper also presents application of these techniques to derive some relevant geotechnical parameters for numerical analysis to determine the stability of slopes in terms of factor of safety.