Risk assessment and support design optimization of a high slope in an open pit mine using the jointed finite element method and discontinuous deformation analysis

The stability of high jointed slopes has an important impact on the construction of engineering projects. Herein, aiming at the high jointed slope of mine, by combining the jointed finite element method (JFEM) and the discontinuous deformation analysis (DDA) method, a whole-of-process analysis method was proposed from identification of the slope stability and risk assessment to later optimization of support design. Firstly, the geological generalization model was established according to the results of engineering geological survey. Secondly, JFEM was used to identify the stability and potential sliding surface of slope. Then, the block system model of slope was established based on potential sliding surface, DDA was used to study the instability process of slope, and risk assessment was conducted according to the accumulation range of rock. According to the risk assessment results, whether to undertake industrial production or optimize the support scheme by JFEM was judged. To verify the effectiveness of this method, a typical high jointed slope was taken as a case study. The results showed that the slope was stable under natural condition, the shear failure of leading edge and tensile failure of trailing edge developed upon excavation. According to the accumulation range of rock, the slope was divided into five zones: forbidden operation zone, high-risk zone, medium-risk zone, low-risk zone, and safety zone, and the optimized prestressed anchor cable design scheme was proposed whose prestressed was 2000 kN, length was 60 m, and spacing was 6 m.