The hydraulic fracturing of coal seams in low permeability was influenced by many factors, which made fracture formation and extension direction in the crossing borehole to be hardly determined. In this paper, while the factors such as the physical and mechanical properties of coal and rock, the strata stress and so on were taken into account, analysis was carried out on the stress state around the boreholes by using theoretical derivation and numerical simulation methods. The results showed that the fracture formation and extension direction of the borehole was related to the ratio k of the stress in direction y to the stress in direction x, when k1, the fracture formed in direction y. This study results can provide theoretical guidance for the layout of fracturing boreholes in coal mines.%低渗透煤层井下水力压裂过程中存在着诸多因素的影响,使得穿层钻孔起裂扩展方向难以确定. 在考虑煤岩层物理力学性质及地应力等因素的情况下,通过理论推导并结合数值模拟手段,对钻孔周围的应力状态进行了分析,结果表明:钻孔的起裂扩展方向与y方向应力、x方向应力的比值k有关,当k1时,裂缝在y方向上起裂. 研究结果可为煤矿井下压裂孔的布置提供理论指导.
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