The Research On Deep-hole Blasting Simulation With Interval Charging

Deep-hole blasting technology plays an important role in ore-rock exploring because ofits special properties such as its high safety, the higher energy utilization rate, less pollutionand easier operation. Traditional continuous columnar charging structure has too highdetonation pressure, too short action time of initial effective stress, too fast stress decay andbad breaking effect, which greatly reduce the efficiency of explosive energy. Compared withthe traditional continuation charging structure, interval charging structure has a very widerapplication prospect because of its unique advantages. Theoretical study of deep-hole blastinglags behind the engineering practice. How to use the explosion energy effectively is one of theurgent problems in deep-hole blasting engineering. This paper summarized the recentdevelopment and future trends for the deep-hole interval charging structure, then analyzed theconstitutive model of rock. Finally, the medium damage process, pressure field, stress fieldand velocity field around the deep-hole blasting hole for the different interval mediums (airand water) and different charging structures (radial coupling charging, axial continuousloading and axial interval charging) were studied by the large nonlinear dynamics analysissoftware LS-DYNA. Moreover, the effects of deep-hole blasting for different intervalcharging structures were also studied. The main research results are as follows:(1) The air layer can buffer the effect of explosion energy in the interval chargingstructure, which can reduce the initial detonation pressure peak and improve the blastingeffect. On the conditions of the same mass charging, the air interval charging structure has amore ideal effect in slowing the stress attenuation, prolonging the duration and reducing theexplosive consumption. The air layer in the central interval charging structure can effectivelyregulate the energy distribution, which can reduce the vibration effect of blasting. Comparedbottom initiation with central initiation modes without the initiation delay for the centralinterval charging structure, it is found that bottom initiation can increase the energy utilizationrate and improve the blasting effect, and that the central initiation can decrease the blastingvibration in a certain extent, which can be used in blasting control. The pressure peaks ofdifferent charging structures presented an exponential decay process.(2) Due to the incompressibility of water, the reflected stress wave could be strengthened,which can increase the pressure near the water interlayer. It is unfavorable to the buffer ofexplosion energy and improving the blasting effect, however. Meanwhile, the wall rock wasshattered excessively. Therefore, only considering the lower initial peak pressure, air intervalcharging structure is better than water medium interval charging structure for the deep-holeblasting engineering.(3) The two corresponding medium charging structures have the similar attenuation timehistory curves for the same elements. The equivalent stress peaks of water medium intervalcharging structure are lower than that of the air medium. Although the difference of the equivalent stress peaks for the two mediums is small, it has a good reference value forblasting engineering designing.(4) Compared with the velocity peaks of several air-interval charging structures, thewater-interval charging structure has smaller vibration effect. For reducing blasting vibrationeffect, water-medium interval charging structure is better than air-medium interval chargingstructure. The propagation velocity of stress wave in air-interval charging structure is slightlyslower than that in the water-interval charging structure.