Rockfall in Himalayan Region: Trajectory Simulation, Design, and Analysis of Protective Embankment

Rockfall hazards in the Himalayan Mountain range are a serious concern due to the steep terrain, weak geological structure, and intense seismic activity. Rockfalls are a natural hazard that occurs when large rocks detach from slopes and fall down, potentially causing damage to people and infrastructure. To arrest or deviate the falling rocks, the most effective solution is the construction of rockfall protection embankments (RPE) at the toe of the vulnerable portion of the hill. These embankments are resistant to the heavy impact of rockfall events and have low maintenance and repair costs. This study presents the details of design and analysis of a proposed rockfall protection embankment (RPE) for a rockfall-prone site along National Highway 58, near Saknidhar village of Devprayag District, Uttarakhand, India. A detailed trajectory analysis is conducted for the vulnerable slope to assess the impacting velocity, kinetic energy, and bounce height of the falling rocks. Based on the analysis, countermeasures in terms of RPE and catch ditch are proposed. The RPE is designed based on the peak obtained values from the rockfall trajectory analysis, and its efficiency is assessed using the kinetic-energy criteria based on literature. Furthermore, the dynamic interaction between the falling rock and the embankment is investigated through three-dimensional finite element analysis using PLAXIS 3D software.