Numerical Analysis of Slope Stability in Open Pit Mining Based on an Integrated Geology and Geomechanics Approach

ABSTRACT: The slope stability analysis usually requires consideration of both geological and geomechanical factors. However, due to the limitation in geological model, current slope stability analysis is typically based upon simplified geological frameworks and does not integrate the key geological complexities required to accurately model the geomechanical response to slope excavation. This study presents an integrated geology and geomechanics approach that can readily assess the geomechanical risk of open pit mining while preserving the geology's integrity. The geological model adopts an implicit modeling of radial basis functions to represent the geology generated from mining survey and borehole drill samples. The 3D geomechanical model is based on a non-linear quasi-static finite element method and the mesh is generated directly from the underlying geological framework. The geomechanics simulation adopts the strength reduction method to evaluate the factor of safety (FOS). The baseline simulation results show a FOS of 1.94, which indicates no shear failure on the open pit mine slope. We also investigate the impact of rock mass geomechanical parameters. The proposed workflow permits us to combine a reliable geological representation with a state-of-the-art rock mechanics finite element solver, which can be used to yield a high fidelity slope stability analysis. 1. INTRODUCTION Open pit mining refers to mining directly on the ground surface and is a critical mining type around the globe. Slope failures of an open pit mine may lead to catastrophic consequences such as economic losses and fatalities. As the mining depths of open pits continue to increase with the decrease in shallow mineral resources, slope stability analysis is becoming more and more important (Du et al., 2022; Zhang et al., 2022). Slope stability analysis is one of the most classical areas in geotechnical engineering (Christian et al., 1994; Duncan et al., 2014; Sjöberg, 1996). In spite of the slope analysis using conventional techniques, open-pit mines are still experiencing slope failures, which indicates the need to develop better models which improve the prediction and understanding of slope behavior (Kolapo et al., 2022).