On mechanism and prevention of sympathetic detonation of bench blasting in water-rich fissure open-pit mine
Sympathetic detonation is defined as the phenomenon where the detonation pressure in one borehole causes explosives in another adjacent borehole to be detonated through an inert medium.It can increase the stress wave and the value of peak particle velocity,even causing fly rock to be thrown far away.These effects can impact the safety of blasting operation,slope stability,and blasting effects.Sympathetic detonation was identified by comparing the fluctuation difference of recorded blast-induced vibration signals.To investigate the mechanism of sympathetic detonation and methods of preventing sympathetic detonation in water-rich fissure open-pit mines,numerical simulation and field tests were adopted to analyze the effects of parameters on the occurrence of sympathetic detonation,such as the quantity of donor charge,crack width,and distance between charges.These results indicated that the borehole pressure increased with the decrease in decoupled charge coefficient,the increase of the crack width between boreholes(0.25-1.00 cm),and the decrease in the distance between boreholes.By using a wave-blocking tube,filling rock power,or setting up an air gap,the impact pressure produced by the donor charge was transmitted to the acceptor charge through the water-rich cracks.These methods made impact pressure lower than the critical detonation pressure of the emulsion explosive,which could prevent the sympathetic detonation of the accepted charge.Based on the field tests and simulated results,rock power filling was the best method of preventing sympathetic detonation when there was a single crack between the boreholes.Meanwhile,using a wave-blocking tube with a thickness of 2.6 mm was the best method of preventing sympathetic detonation when there were multiple cracks between the boreholes.Above all,the proposed detection method and obtained technologies provide the theory and guidance for preventing sympathetic detonation,which leads to improved blasting effects and the safety of blasting operations.
sympathetic detonationbench blastingwater-saturated fractured rock masscritical pressure
国家科技期刊平台
NSTL
万方数据
