Analysis of crack extension and energy dissipation under coupling action of in-situ stress and explosion load

Crack extension and energy dissipation under conditions of coupled in-situ stress and explosion load tend to exhibit different patterns than under single stress field conditions. This study derives the coupled stress calculation expression of in-situ stress and explosion load, discusses the distribution characteristics of coupled radial stress and coupled tangential stress, and analyzes the change rule of coupled stress with explosion center distance and angle. Methods for calculating the extent of the crushed zone, fractured zone and blast energy under in-situ stress are presented. The influence laws of axial loading coefficient, lateral pressure coefficient, dynamic compressive strength and dynamic tensile strength on the extent of crushed zone, fractured zone and explosive energy distribution are analyzed. The results show that there is a suppression and orientation of the coupled stress field by the in-situ stress. Under the coupling action of in-situ stress and explosion load, the cracks around the blasthole are approximately distributed in an “X-shape”. Axial loading coefficient, lateral pressure coefficient, dynamic compressive strength and dynamic tensile strength have an important influence on the extent of the crushed zone and fractured zone under the action of the coupled stress field, as well as on the law of explosive energy dissipation. The results of the study can provide a reference for safe and efficient blasting and vibration active prevention and control in tunnels and underground spaces.