Study on Distribution Characteristics of Damage Range along Smooth Blasting Hole Based on PPV

The damage range of surrounding rock has an important influence on optimization of blasting parameters. This study, based on the vibration attenuation law near the blasting source and the characteristics of the load acting on the wall of the smooth blasting hole, derives the distribution formulas of the damage range along the borehole during the expansion and quasistatic processes of detonation gas, respectively. More importantly, the quantitative relationship between the damage range and the charge weight of the single borehole is established. The experimental data are used to verify the correctness of the theoretical formulas. The results show that the damage range during the expansion process of detonation gas presents a continuous saddle-shaped distribution along the borehole and the maximum damage range is near the charge segment. The damage range during the quasistatic process of detonation gas is uniformly distributed along the borehole and can be more conservatively used to the practical prediction after corrected. The theoretical formulas are applicable to the perimeter hole with the radial and axial decoupled charge structure, which can provide a theoretical support for controlling the damage range of surrounding rock according to the charge weight