大直径空孔直眼掏槽爆破效果的实验研究

直眼掏槽中空孔对掏槽具有重要影响,以大直径空孔直眼掏槽和小直径空孔直眼掏槽为研究对象,通过理论和数值模拟分析了大直径空孔直眼掏槽破岩机理,结合实验室实验分析不同直径空孔直眼掏槽的爆破效果。研究表明:空孔直径对直眼掏槽的爆破效果和爆破振动均产生重要影响,小直径空孔振动速度峰值、振动持续时间等参数均高于大直径空孔掏槽,大直径空孔比小直径空孔爆破振动速度降低20.6%;大直径空孔掏槽爆破掏槽深度提高20%,对掘进工作面的破坏范围减小30.8%;结合掏槽效果及爆破能量分析,大直径空孔直眼掏槽由于空孔提供的自由面较大,振动消耗炸药能量要小于小直径空孔掏槽,大部分能量用于掏槽区岩石的破坏,减少了爆破振动危害。

Experimental Study on Parallel Cut Blasting Effect of Large Diameter Empty-hole

The empty-hole of parallel cut has an important influence on the cutting effect.Taking large-diameter empty-hole parallel cut and the small-diameter empty-hole parallel cut as the research objects,we analyzed the rock breaking mechanism of large-diameter empty-hole parallel cut through the theory and numerical simulation,and analyzed the blasting effect of empty-hole parallel cut with different diameters by combining with laboratory experiments.The research shows that the diameter of the empty-hole has an important influence on the blasting effect and blasting vibration of the parallel cut.The parameters such as the peak velocity and vibration duration of the small-diameter empty-hole are higher than those of the large-diameter hole.The blasting vibration velocity of large diameter empty hole is 20.6%lower than that of small diameter empty hole.The cutting depth of large-diameter parallel cut blasting is increased by 20%,and the damage range of tunneling working face is reduced by30.8%.Combined with the analysis of cutting effect and blasting energy,the vibration consumption of blasting energy in the parallel cut with large diameter empty hole is smaller than that of the small-diameter empty-hole parallel cut due to the large free surface provided by the empty-hole.Most of the energy is used for the destruction of the rock in the cutting area,which reduces the damage of blasting vibration.