Numerical modelling of dynamic testing for rock reinforcement used in underground excavations

As mines have expanded due to increased depth, new challenges have appeared for mining engineers. Highstress environments, where there are rockburst events caused by energy release, have become especially interesting in terms of geomechanics and have prompted changes in conventional designs, demanding more research into how underground excavations absorb dynamic impacts. For these underground excavations, the development of new reinforcement elements capable of both resisting dynamic loads and yielding in the process without failing has advanced in the last 30 years due to studies and testing programs carried out by recognised institutions. However, executing these testing programs implies a high cost in time and validation. Hence, a limited number of these have been completed. In this context, numerical modelling to represent the performance of the process and enhance laboratory testing has become increasingly necessary and relevant. In this paper, a numerical modelling methodology based on the finite difference method has been applied in order to predict the behaviour of threadbar, commonly used in Chilean mining as reinforcement in underground excavations, in dynamic load testing. Accordingly, a comparison and calibration of the numerical model with laboratory-scale dynamic tests from previous research is presented.