Empirical Slope Stability Assessment Along the Road Corridor NH-7, in the Lesser Himalayan

Stability assessment in active Himalayan region is very crucial, as the area has many phase of deformation and complex geological condition. Further the development activities and road settlement enhanced the slopes instabilities issues. The present article emphasizes empirical slope stability assessment to characterize the rock mass, failure types and stability analysis. For this eighteen different vulnerable slopes have been recognized between Devprayag and Srinagar in Uttarakhand (Lesser Himalayan), along the NH-7, which goes to Holy shrines Shri Kedarnath temple. Geometrical and kinematic investigation for each slopes have been assessed for structurally controlled rock mass which shows mostly wedge type of failure with planar and toppling failure. The empirical analysis between rock mass rating (RMR) and Geological Strength Index (GSI) characteristic show a linear relationship for particular rock type. The road corridor has generally fair to good variety of rock mass characteristic as from RMR description. The new system as Qslope and slope mass rating (SMR) system have been associated to distinguish the stability problem, which described comparatively same type of stability. The designed slope angle β for the Qslope value has also been evaluated for different probability of failures for the stability of each cut slope. This new Qslope empirical method compared with SMR method for fractured rock slopes will give the better perception to care the stability issue with simple, reasonable and prompt approach to design and develop the road corridor in hilly region.