Numerical Simulation of the Dynamic Breakage Testing of Sandstone, Part I: Development of Homogeneous Constitutive Model for the Fragmentation Analysis in Sandstone

Laboratory drop weight tests rig and numerical modelling have been used to investigate the impact energy effect on the degree of dynamic fragmentation of cylindrical rock samples. The drop weight tests indicated that the degree of dynamic fragmentation of the Daley Dale sandstone formed a non-linear relation with impact energy. In the numerical modelling of the drop weight test, the shear localisation developed in the Daley Dale sandstone was assumed to represent discrete fracture planes. Shear bands, outputs of the image analysis of the numerical model, were used to separate solid material from shattered or broken material, allowing the FLAC output from the dynamic modelling to be processed into black and white fragmented images. This was undertaken to determine particle size distributions. Corresponding grading curves from the numerical modelling were then validated against the laboratory derived curves indicating the potential of numerical modelling to simulate the process of rock fragmentation.