ASSESSMENT OF ROCKFALL HAZARD OF HILL SLOPE ALONG MUMBAI-PUNE EXPRESSWAY, MAHARASHTRA. INDIA

The rockfall hazard in high hills of deccan pleatue has been one of the major disasters in western part of India. The present study aimed to assess the stability of hill cut highway slope near Khandala tunnel along Mumbai-Pune expressway, Maharashtra, India. This study is significant as the Khandala tunnel is one of the five tunnels situated along the Mumbai-Pune expressway, which experiences frequent rockfall and slope instability, mostly in the rainy season. The assessment of slope failure in the present study performed by a combination of rockfall simulation and 2D slope stability analysis. The results of the slope analysis show that the slope is stable in dry condition having a factor of safety (FoS) 1.48. In contrast, it becomes very critical during the rainy season having FoS of 1.07. Rockfall analysis shows that the boulders came down on both carriageways with approximate maximum bounce height, total kinetic energy, and translational velocity of 9 m, 500 kJ, and 16 m/s, respectively. The preventive slope stabilisation measures suggested to minimise the failure problems and to capture the movement of falling blocks before reaching the road.