Fractal damage and crack propagation in decoupled charge blasting

Abstract

Decoupling coefficient and filling medium are the two key influencing factors that affect the effect of decoupled charge blasting. Using the model experiment method, combined with the fractal damage theory and the energy release rate theory, the fractal damage of the breakage zone, the fracture zone and the crush zone in coupled charge blasting and decoupled charge blasting (respectively using air and clay as the filling medium) is studied, and the energy release rate of the blast-induced crack is analyzed. In decoupled charge blasting, the filling medium plays a role in buffering and weakening the transfer of blasting energy, which inhibits the formation and development of the crush zone and reduces the fractal damage in the breakage zone. However, different filling media (air and clay) have significant differences in the formation of the fracture zone. Reasonable decoupling coefficient can make the energy carrying of the blast-induced crack more concentrated and increase the propagation length, thereby increasing the range of the fracture zone and improving the fragmentation effect.