Study on energy evolution and crack propagation of rock mass under single hole uncoupled charge blasting

In drilling and blasting operation, uncoupled charge structure is widely used in pre-split blasting, smooth blasting, pressure relief blasting and other controlled blasting engineering. In order to study the evolution of energy and crack propagation in rock mass during blasting under the uncoupled charge structure, this paper established a three-dimensional numerical test model of single-hole uncoupled charge by numerical simulation method. By changing the uncoupling coefficient, the pressure of hole wall, energy evolution and crack propagation during blasting were compared and analyzed. The results show that under the condition of the same explosive quantity, the strain energy of rock mass, the strain rate and peak pressure of hole wall rock and the area of blasting crack are negatively correlated with the uncoupling coefficient of charge, and the formula of the change with the uncoupling coefficient is obtained. When the uncoupling coefficient is less than 3 and the charge uncoupling coefficient is changed, the peak pressure of hole wall, strain energy of rock mass and blast-induced crack area decrease significantly with the increase of the uncoupling coefficient. When the uncoupling coefficient is greater than 3, the change range of the uncoupling coefficient becomes smaller. The experimental conclusions are analyzed to provide reference for field blasting construction.