An investigation into the time dependent deformation behaviour of open pit slopes at Gibraltar Mine, BC, Canada

Open pit slope instabilities experience a sequence of decelerating deformation events following changes in stress state due to blasts or mining. These deformation events are poorly understood. This thesis uses large databases of specific energy and slope radar monitoring data to characterise five slope instabilities. Eight different rheological and empirical curve-fitting models are applied to 24 deformation events to identify which model best approximates observed deformation. The best-performing model, the Fractional Maxwell model, is then applied to nearly 200 deformation events identified from the five slope instabilities. The resulting model parameters α, fractional viscosity, and A, magnitude of the response, are tracked and compared with deformation history, instability size and geometry, and blast size and location. Slope instabilities exhibit increasingly viscous behaviour with deformation as damage accumulates within the rock mass. The magnitude and likelihood of deformation events correlate with the proximity of the stress change to critical geological structures.