Study on the formation of rock mass cracks based on the interval charge structure with constant blasting energy

Abstract

In order to solve the problem of energy concentration of traditional continuous charge and poor quality of pre-splitting surface in deep hole pre-splitting blasting, this study aims to explore the efficient and uniform utilization of explosion energy by optimizing the structure of axial interval charge under the premise of constant total blasting energy, so as to form a continuous and flat pre-splitting surface. Under the constraint of constant total charge and total charge length, the method of combining theoretical analysis with numerical simulation is adopted. The three-stage fracture mechanism of interval charge is explained from the mechanical theory, and the double-hole pre-splitting blasting model is established based on LS-DYNA software. Three kinds of interval charge schemes of three sections, four sections and five sections are designed systematically, and the blasting effects are compared. The numerical simulation results show that the number of charge segments plays a key role in regulating the energy distribution and stress field morphology under the condition of constant total energy. Through comparison, it is found that the four-stage charge scheme achieves the best balance between energy concentration and dispersion, and can form a continuous, uniform and lasting tensile stress field, which is most conducive to the straight penetration of the pre-splitting surface. The three-stage and five-stage schemes have the defects of uneven distribution and insufficient driving force, respectively.