Stability Assessment of Reinforced Rock Slope Based on Two-Dimensional Finite Element Approach: A Himalayan Case Study

Abstract

Himalayan rock slopes are highly vulnerable to landslides due to geological and tectonic activities. The study area lies along NH 109 road from Rudraprayag, the only pilgrimage route to holy Kedarnath, which experiences high vehicular traffic. There are many cases of landslides reported due to the unpredictable weather and landslide-prone rocks in this seasonal pilgrimage route. Stability analysis is essential, and effort should be given to understand their failure mechanism which resembles the actual field instability. It is important to take mitigation measurements to minimize the losses due to slope failure and to ensure the safe transportation along this route. In this case study, stability analysis of the rock slope, located on national highway (NH 109), is performed using Phase² of Rocscience software by considering rock mass as continuum. Reinforcement is provided for the protection of vulnerable rock slope. Two methodologies, equivalent continuum method and combined continuum-interface numerical method, are adopted for the analysis. Equivalent continuum model considers rock slope as continuum mass without any joints, and the effect of discontinuity is introduced by reducing the strength and properties of intact rock to that of the jointed rock mass. In the combined continuum-interface numerical method, the joints are explicitly introduced in the numerical model which accurately represents the behavior of rock slopes in actual field condition. Based on this analysis, end-anchored rock bolts are given as reinforcement to achieve the target factor of safety against failure.