Stochastic Rock Slope Stability Analysis: Open Pit Case Study with Adjacent Block Caving

In last decades, numerical modelling become a useful tool for solving complex geoengineering problems such as slope stability. On the other hand, probabilistic slope stability analyses are able to consider the variability of the rock mass properties in the decision making process. However, the application of probabilistic slope stability analysis with large three-dimensional numerical models is still limited due to the computational expenses of evaluating a substantial number of considered models. It is well-known that response surface methodology (RSM) couples the mathematical and statistical techniques to relate input variables to the response, allowing a reliable outcome and reasonable time of the analysis. Taking these advantages, this article presents an application of RSM in probabilistic slope stability analysis using three dimensional distinct element modelling. For this purpose, the most influencing factors including: uniaxial compressive strength, geological strength index (GSI), and shear strength of discontinuities, were taken into consideration to determine the probability of failure of an open pit slope located in vicinity of a block caving-induced subsidence crater. Numerical analysis of slope stability was conducted for an open pit slope using the Distinct Element Method code-3DEC. Probability distribution of the factor of safety (FS) was determined and possible slope failure mechanism was observed. In addition, the block caving-induced subsidence was investigated. The final outcomes indicate that Response Surface Methodology is applicable when couples with numerical modelling of complex issues, GSI is considered the most influential variable. The studied slope is considered stable due to the low value of the FS probability distribution (2.2%). This research is expected to provide a reference for slope stability analysis in case of transition from Open Pit to Underground Mining.