THE CHALLENGE
- Large open pit mine undergoing significant wall deformations and instabilities.
- Complex system behaviour characterized by an interplay of major discontinuity surfaces (faults and foliation) and groundwater flow.
- Back analysis to understand the deformation and failure mechanisms of the open pit and calibrate the model for subsequent forward-analyses of future cutbacks.
- Conventional tools fail to correctly capture the main processes involved as they require numerous simplifying assumptions.
THE SOLUTION
- Irazu is well suited to analyze the mechanical behaviour of rock slopes and can capture a wide spectrum of slope behaviours without the need for complex constitutive models, including continuum deformations, fracturing and complex failure kinematics, and large displacements.
- A large number of faults and other discontinuity surfaces can be included.
- Groundwater pore pressure effects (e.g., effective stresses) can be taken into account together with coupled flow of water through rock fractures.
THE RESULTS
- Successfully back-analyzed the wall deformations of the current cutback with realistic deformation and acceleration patterns.
- Quantified the effect of pore pressure on slope performance, confirming that groundwater flow through the faults could create large deformations on the slope.
- Predicted the performance of future cutbacks under different geomechanical scenarios, including excess pore pressure and provided ranges of expected slope wall deformations.
- Suggested remediation strategies, such as dewatering campaigns, to further stabilize the slope, thus cutting costs and increasing mine safety.
