为提高煤炭资源回收率,缓解采掘接替紧张,避免因留设煤柱产生的煤矿地质灾害,切顶留巷技术已成为煤矿煤炭开采的主要方法,为研究不同切顶炮孔间距对岩石顶板的爆破切顶的影响,利用有限元模拟软件LS-DYNA,建立有、无地应力双孔预裂爆破模型。依次设置炮孔间距为10、12、14、16倍炮孔直径,结合数值模型的有效应力云图、有效应力时程曲线和炮孔间裂纹扩展等结果综合分析选择最优的炮孔间距,并在现场进行试验。结果表明:地应力对炮孔裂纹有抑制作用;在地应力状态作用下,两炮孔裂纹贯穿距离为9~11倍炮孔直径效果最好,且对周围岩体的损伤较小,与现场钻孔窥视结果一致。

In order to improve the recovery rate of coal resources, alleviate the strain on mining and excavationstress cloud diagram, effective stress time history curve, and crack propagation between blast holes. Field tests are then conducted based on the selected blast holes. The results show that in-situ stress has an inhibitory effect on blast hole cracks. Under the in-situ stress state, the crack penetration distance between two blast holes is 9 to 11 times the blast hole diameter, which has the best effect and causes less damage to the surrounding rock mass. It is consistent with the field drilling peep results.