掏槽参数对煤矿岩巷爆破效果的影响

Influences of cut parameters on blasting effect in rock roadway of coal mine

为了提高掘进进尺,以川煤集团绿水洞矿掘进工程为背景,利用动力有限元程序LS-DYNA3D进行掏槽参数优化研究。结合井下现场实验,分析岩巷掏槽爆破不同参数动态应力、破碎范围的变化以及井下实际爆破效果。掏槽中心孔底向孔口平均有效应力峰值在有中心眼爆破较无中心眼爆破时增加了40%以上,中心眼爆破对槽腔底部的形成起主要作用。在其他条件相同的情况下单孔载荷从1.2kg提高到1.8kg,掏槽区中心眼底到孔口平均应力只增加20%,并且破碎范围的增加较少,实际进尺增加小于10%。现场掘进实验表明：在常规爆破载荷下,有中心眼比无中心眼爆破深度提高31%-65%,掏槽角小于78°时,随掏槽角度增加爆破进尺下降较平缓;但掏槽角增至82°左右,随掏槽角度增加爆破进尺下降明显。

To improve the driving speed, by taking the tunnel blasting practice in Lushuidong coal mine as research background, the optimization of cut parameters was studied by LS-DYNA3D. Underground field experiments were combined to analyze the dynamic stress, hard rock-crushed range and underground blasting effect for the hard rock cut blasting with different parameters. The average effective stress peak, along the section of the cut center from the bottom of the hole to the top, increases by over 40% when the center holes are blasted as compared with that when the center holes are not blasted. Center hole blasting plays an important role in the formation of the groove bottom. Under the same conditions, when the explosive charge in each blasting hole increases from 1.2 kg to 1.8 kg, the average effective stress peak along that section increases by only 20%, the hard rock-crushed range increase by less, and the advance per attack adds within 10% in blasting practice. Field experiments show that the cut blasting depth increases by 31%-65% with center holes blasted as compared with that without center holes under normal blasting charge condition. When the cut angle is less than 78%, the blasting footage decreases slowly with the increasing of cut angle; when the cut angle increases to 82%, the blasting footage decreases obviously with the increasing of cut angle.