Impact of Road Widening on Slope Stability in the Hilly Regions

This book encompasses various aspects of landslide investigation in the hilly regions and lays emphasis on site specific field observations and kinematics in understanding the slope failure mechanism. A case study was undertaken along the National Highway between Jammu and Udhampur in Jammu and Kashmir State (India) in the Northwest Himalaya. Field observations along with the data sets on the slope aspects, precipitation and joint sets were collected and analyzed. The study reveals that the hill slopes comprising of fragile and water sensitive lithologies (sandstone-mudstone alternations) become more vulnerable if timely adoption of preventive measures are not taken into account during road widening processes. The slope cutting for road widening modifies the landscape including increase in slope angle and toe cutting, and exposes new surfaces to erosion due to surface run-off during incessant rainfall and result in the formation of rills and gullies. During prolonged and continuous rainfall these rills and gullies further aggravate slope failure mechanism and result in large landslides. In addition to this loss of the angle of repose also results in slope failure due to gravity.