Slope Stability Analysis of Coalmine Overburden Dump Using a Probabilistic Approach

During process of coal mining, overburden materials are removed to reach the coal seam. Overburden materials are composed of soil, rock, and other debris that are stored in the vicinity of the mining area in the form of dumps. These materials are often heterogeneous, hence their properties such as density and strength can vary greatly from one location to another. Thus, to assess the stability of the overburden dumps, a probabilistic analysis is desired over a deterministic analysis. In this study, a typical overburden dump geometry has been considered where the top 1 m of the slope is considered to comprise vegetation. A 2D limit equilibrium analysis has been performed where the material heterogeneity has been incorporated by considering the probabilistic descriptors i.e., mean, standard deviation, and coefficient of variation (CoV). The effect of CoV on the overburden and vegetative layer material properties is studied at different intervals using Monte Carlo (MC) method. The results obtained are compared with the results of the bare dump slope (without vegetation). The factor of safety from the deterministic analysis and the probability of failures for various cases for the bare and vegetated dump slope are compared. The findings offer significant perspectives on comprehending how the slope stability assessment of coal mine dumps is affected by material heterogeneity and a vegetative layer.