Numerical Modelling Based Sensitivity Analysis of Stability of an Overburden Dump Slope

Abstract

Abstract Globally, design-based shortcomings caused many dump slope instability in the last two decades. Thus, the reliable design and a thorough understanding of the influencing parameters of an overburden dump structure is critical for its safe operation and maintenance. This paper reports a numerical modelling-based sensitivity analysis to develop an approach for designing an optimally safe dump structure in a limited space. The study was based on the large scale opencast workings of central India. The geometrical dimensions of dump structures were compiled from the major opencast workings, and geotechnical properties were based on the laboratory findings of geotechnical tests conducted on the dump material. The effect of total dump height, bench height, bench slope angle, bench width, cohesion and friction angle were evaluated considering a strong floor through the numerical simulation using FLAC 2D software. The friction angle possessed highest and total dump height had least influence on the dump slope structure. The FoS can be less than 1 even if a single bench fails instead of the entire dump structure. Hence, Displacement and shear strain parameters were incorporated in this study along with the safety factor to identify the instability prone zones. The statistical analysis was performed using SAS v7.15 software to determine the combined effect of considered stability governing parameters on the stability of dump structure by developing a mathematical model. The R-Square of the model was 0.988 with a standard error of 2.54%. The classification of output parameters is also done to deduce the state of stability.