Rock Cut Slope Stability at Sohna on NH-919, Gurgaon

Landslide is a disaster that has frequently been occurring along the rock cuts in hilly regions leading to the damage of road and rail infrastructure as well as loss of lives. Our study is to revisit a hill crossing road constructed some 50 years ago, now subjected to more traffic in terms of numbers, bigger and heavier vehicles, putting more wear and tear of roads. The study area is located in Sohna along NH-919, a National Highway connecting Palwal to Rewari. A rock cut slope stability assessment was carried out along 370 m long stretch on the Sohna Hill. This stretch is precarious and has a long slope exposed along road. Our study has been carried out at three locations almost 100 m apart, for investigation and evaluation of the hazard potential. Based on field observations, the rocks were found to be Quartzite with some local presence of Schists. As such presently no protection measures are provided along the cut for safety purposes. The hazard potential has been worked out by incorporating method Landslide Susceptibility Score (LSS). The LSS values shows that the slope as moderately susceptible to landslide hazard. The study finds that due to indiscriminate mining in the past, increased traffic in terms of number and nature and coming up a newly built Freight corridor of railways may have detrimental effect on the slope. Recent earthquakes, with epicenter around the study area and sporadic events of heavy rainfall warrant a relook on the safety measures along the road, which are none at this juncture. The remedial basic preventive measures such as toe ditch, double twisted wire mesh system are needed to be installed.