Slope Stability Assessment by Using Rock Mass Rating and Kinematic Analysis Along NH-5 from Kandaghat to Waknaghat, Himachal Pradesh, India

Himalaya is among the world’s most landslide prone areas. The North-West lesser Himalaya is prone to different geohazards such as landslides, earthquake and flood etc. The present study is mainly focused on the slope stability assessment by using rock mass rating and kinematic analysis along national highway- 5 (NH-5) from Kandaghat to Waknaghat, HP, India. It is one of the important highways, which carries millions of tourists, acts as a main means of transporting the men and material all through the region of Kinnaur district including border areas. The incidence of landslides in the study area has been escalating since the beginning of highway construction. However, the incidences of the landslides have reportedly increased due to the subsequent unplanned anthropogenic activities including the recent widening of the highway. One lane of the NH-5 has been completely closed for public transport at some vulnerable locations to reduce risk of fatality and property. The joint plane data has been taken in the field from different site slopes and which have been used for making stereo plots to determine different modes of failure using kinematic analysis. Then Rock Mass Rating (RMR) and Slope Mass Rating (SMR) have been calculated to examine the various classes of slopes. As per the RMR scheme, all the three rock slopes fall in fair class. Based on kinematic analysis, 2 rock slopes highlight wedge failures and 1 slope shows conditions for planar and wedge failure.