Numerical Simulation of Smooth Blasting Considering In-Situ Stress and Pre-Blast Hole Damage

To investigate the effect of pre-blast hole damage and in-situ stress on the evolution of damage in the smooth blasting of rocks at different burial depths, the damage threshold of 0.5 was first determined for the RHT model applicable to smooth blasting using 2D numerical simulations. A 3D model was then established and the ANSYS-DYNA implicit-explicit sequence solution method was used to apply in-situ stress to the model, and the equivalent stiffness was discounted to account for the damage of the pre-blast hole to investigate the distribution of rock damage in space. The results show that the presence of in-situ stress has an inhibitory effect on the deep rock blasting damage, and this inhibitory effect will increase with the depth of burial. The pre-blast hole damage to the rock catalyses the next smooth blasting to break the rock. When smooth blasting is carried out at different burial depths, the choice of the best smooth blasting layer thickness and the smooth blasting hole spacing is not the same. When considering both the pre-blast hole damage and the impact of in-situ stress, if the depth of burial is small, the two values should be appropriate to increase, if the depth of burial is larger, the two values should be appropriate to reduce with the increase in depth.