Analysis of the blasting effect of strip cartridge position on jointed rock mass

Abstract

In order to study the failure pattern of single jointed rock mass caused by the position of the hole of the strip cartridge, dynamic caustic method, fractal theory and high speed photography technology were combined. The derivative crack propagation pattern of defects in adjacent rock strata under blasting and the evolution of the damage of rock strata, where the hole was located, were analyzed. The results show that, with the increase of the distance between the borehole and the joint, the effect of the reflected stress wave near the joint weakened, and the damage on both sides of the borehole and the bottom of the borehole exhibited different variation patterns. The damage on both sides of the borehole decreased gradually, whereas the damage at the bottom of the borehole increased gradually. The defects in the vertical joint direction were present in the adjacent rock strata. The results showed that the influence of the explosion transmission wave on the defects in different positions was different. The defects near the initiation center were destroyed mainly by compression shear, whereas the derivative crack propagation length was small. The defects far from the initiation center were damaged mainly by tensile shear, while the derivative crack propagation length was long.