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运用LS-DYNA对控制孔距离爆破孔不同间距的煤体进行深孔预裂爆破数值模拟,研究控制孔距爆破孔的远近对裂隙演化规律的影响,结果得出:受应力波与自由面反射效应的拉应力叠加作用,距离控制孔3 m的爆破孔周围能够形成10~13条的主裂纹,且其中存在的长裂纹甚至几乎贯通煤体,对煤体尖端应力强度好于4.5 m孔间距。通过试验区内将抽采孔瓦斯浓度和瓦斯抽采纯量作为2项指标在距离爆破孔3 m和4.5 m范围内进行对比,得出孔间距3 m时比4.5 m时要明显增加,说明孔间距为3 m时增强了钻孔周围的卸压效应,证明试验区有效卸压半径为3~4.5 m,与数值模拟结果吻合。
Using LS-DYNA, the numerical simulation of deep-hole presplitting blasting of coal with different spacing from the blast hole in the control hole was carried out to study the influence of the distance between the control hole and the blasthole on the evolution of fracture. The results show that the stress- Effect of the superposition of tensile stress, from the control hole 3 m blasthole around the formation of 10 to 13 of the main crack, and the presence of long cracks even almost through the coal, the tip of the coal stress intensity better than 4.5 m hole spacing . Comparing the gas drainage density and the gas drainage volume in the test area as 3 indexes within 3 m and 4.5 m from the blasting hole, it is found that the hole spacing at 3 m is obviously higher than that at 4.5 m, indicating that When the hole spacing is 3 m, the relief effect around the borehole is enhanced, and the effective pressure relief radius in the test area is 3 ~ 4.5 m, which agrees with the numerical simulation.