Half Tunnel Rockfall Simulation in Himalayas Region- A DEM Approach

Abstract

Rockfall is a common geological hazard in the Himalaya, particularly along road cut slopes developed in steep mountainous terrain. Rapid infrastructure expansion and unscientific excavation, drilling, and blasting practices have significantly increased slope instability and overhanging rock masses. This study investigates rockfall characteristics along National Highway-05 between Tranda and Jeori in Himachal Pradesh, India. The rock mass mainly comprises schistose rock with more than three persistent joint sets under moderately weathered and damp conditions. Field data on rock mass properties and discontinuity geometry were collected and analyzed using distinct element modelling and rockfall simulation techniques. The study evaluated block trajectories, fragmentation behavior, and impact energy of falling rocks. Highly vulnerable blocks were identified for controlled blasting and stabilization, which can significantly improve long-term slope stability and road safety.