Explosion wave and crack field of an eccentric decoupled charge.

Abstract

To investigate the characteristics of the explosion damage from an eccentric decoupled charge, the rock-breaking mechanism of an eccentric decoupled charge is revealed from the perspectives of the explosion wave field and crack field through theoretical and experimental analyses. The ratio of the maximum to minimum pressure on an eccentric decoupled hole wall increases exponentially with an increase in the decoupling coefficient, but it does not change with a change in the explosive density or explosive detonation velocity. The explosive energy on the eccentric charge side has a certain accumulation effect, the velocity of the reflected shock wave at the blasthole wall is greater than that of the incident shock wave, and the incident velocity of the explosion wave on the eccentric side is greater than that on the non-eccentric side. The expansion range of the explosion gas is significantly better than that on the non-eccentric side, indicating that the eccentric decoupled charge can strengthen the action of the explosion gas product on the eccentric side. In addition, the overpressure of the explosion wave on the eccentric side is greater than that on the non-eccentric side. The fractal dimension and damage degree of the explosion crack on the eccentric side are larger than those on the non-eccentric side. The explosion cracks can be divided into intensive, transition, and sparse areas, and the fractal dimension and damage degree decrease successively in the three areas. The explosion cracks formed on the non-eccentric side outside the range of three times the blasthole diameter concentrate in the sparse area, and the destructive effect of the explosion on the non-eccentric side medium is effectively reduced.