Geomechanical interpretation of the Downie Slide considering field data and three-dimensional numerical modelling

Downie Slide has been interpreted as a massive, composite rockslide, and a number of landslide zones have been defined based on the interpretation of morphological features and a detailed assessment of spatially discriminated slope behaviour. Key factors controlling the mechanics of massive slow-moving landslides can be interpreted through the observation and detailed study of the slope behaviour and physical characteristics. Once identified, key components influencing slope deformation can be tested using three-dimensional numerical models. Two series of numerical simulations have been developed to test how explicitly defined internal shear zones, and the interaction between landslide morphological regions, influence global landslide behaviour. Results from these numerical simulations, when compared to field monitoring data, indicate that internal shear zones have little influence on Downie Slide deformation, while the interaction between morphological zones plays a larger role in slope kinematics.