针对目前倾斜煤层起裂机制不明确，导致水力压裂时盲目升高压力或增大注水量来增加煤层透气性的问题，根据最大拉应力理论，分析真实环境下倾斜煤层压裂钻孔周围应力状态，建立压裂钻孔周围煤岩体起裂压力计算模型及判断准则，并在重庆松藻煤电公司同华煤矿进行了验证，结果表明，根据实测压裂区域地应力状态，起裂压力随煤层倾角增大而增大，钻孔起裂位置随煤层倾角增大逐渐向走向方向偏转；现场试验起裂压力与理论计算相符，随煤层倾角增大而增大，从而验证了计算模型的正确性。

As for the problem of ambiguous mechanism of crack initiation in inclined coal seam, it leads to a blind increase in water pressure or water injection rate to enhance the coal seam permeability during hydraulic fracturing in underground coal mines. In this paper, the stress state around the fracturing boreholes is analyzed using the in-situ stress coordinate conversion, then a model is established using the maximum tension stress (MTS) theory to calculate the initiation parameters of the borehole rocks. The influences of in-situ stress and coal seam inclination on the hydraulic fracturing initiation pressure and locations in underground coal mines are investigated using the model. The field test is conducted at Tonghua coal mine of Chongqing Songzao Coal and Electricity Co. Ltd. .The results show that: according to the stress state in fracturing area, the crack initiation pressure increases along with the increasing coal inclination. With the increase in the coal inclination, initiation location moves to the strike direction. The results in field test are consistent with the calculated result which is that initiation pressure increases along with increasing coal inclination. It verfies the feasibility of the calculation model.