Numerical Simulation of Single Hole Blasting of Rock Based on the Material Point Method

The drilling and blasting method is the main rock-breaking means in mineral resource mining, and its theoretical analysis imposes great limits on the applicable conditions. Moreover, the blasting experiments have limitations such as high costs, and difficulty in observing the cracks formed after blasting. Numerical methods have become an important supplementary means to explore the comprehensive fracture mechanism of rock explosion. A 2D material point model coupled with the generalized interpolation material point (GIMP) and the conjugate particle domain interpolation material point (CPDI), was proposed to analyze effects of the background mesh and material point discretization sizes. The results show that, the discretization sizes of the background grid and material points significantly influence the transfer of explosion energy, and the degree of damage to the rock is positively correlated with the total energy transferred from the explosive to the rock. In the simulation of the fracture failure under rock blasting load, the GIMP-type material points are suitable for simulating extreme compression deformation in explosive core areas. In contrast, the CPDI-type material points are more appropriate for simulating rock blasting damage situations. Under the action of detonation waves, the compressive stress on the borehole wall exceeds the rock compressive strength, leading to the rock crushing destruction, and a severely damaged area appearing around the borehole. The detonation wave continues to propagate and attenuate into a stress wave, and the hoop stress wave propagating along the radial direction will generate a larger tensile stress in the circumferential direction, leading to the formation of radial cracks.