Fragmentation of rock under dynamic loads

Abstract An approach is described for predicting fragment size distributions for rock under dynamic loading conditions. The approach is (1) to determine the nature and order of the physical processes occurring in the rock during loading that lead to fragment formation, (2) to treat each process computationally and (3) to insert the resulting fragmentation model into a wave propagation code which calculates the stress history in the rock caused by the dynamic load. The approach was applied to Arkansas novaculite under one-dimensional-strain impact loads. Plate slap experiments were carried out to support model development and determine values of those rock properties required for the model. A calculation was made to simulate the conditions of one of the dynamic impact experiments and compute the resulting fragment size distribution. The agreement between calculated and measured fragment size distribution illustrates that fragmentation behavior can be predicted from a few measurable rock properties.