Characterization of blast damage in rock slopes: An integrated field-numerical modeling approach

Consideration of blast damage in rock slope stability has been a challenging task in rock mechanics because blasting results depend on several factors that can lead to different forms of damage. Currently, it is not clear on how to consider blast damage in rock slopes. This thesis investigates the occurrence of blast damage in rock slopes using an integrated field investigation, remote sensing and numerical modelling approach. A framework for defining blast damage in the field and using remote sensing data was developed to provide the input for a blast damage model which can then be used either for numerical analysis or understanding the occurrence of blast damage features in the field. Results of field investigation and numerical simulations show that blast damage on the rock slope surface varies depending on the rock mass quality. Blast fracturing increases with decrease in rock mass quality. Observations on exposed joint surfaces in open pit slopes indicate that the blasting process has induced varying forms of damage on these surfaces. Finite-discrete element numerical modelling of blast induced damage indicates that blast damage develops in different forms from the slope surface. The simulated blast damage zone varied from complete blocks (fully connected blocks), partially connected blocks, dilation and undamaged zone. The extend of the blast damage increased with decrease in strength of the rock. A stronger rock mass show less blast damage thickness compared to a weaker rock mass. Results show that blast damage features such as blast fracture, damage along the joint surface and extension of joints all influence slope stability.