摘要
为了研究煤矿井下水力压裂初始裂纹起裂条件和起裂方向,在线弹性断裂力学的基础上,建立了圆形孔楔形切槽水力压裂断裂力学模型,模型切槽长度与钻孔直径接近,综合计算分析了水力压裂裂纹尖端应力强度因子。根据切槽尖端应力强度因子,运用复合型裂纹脆性断裂的最大环向拉应力理论,分析了裂纹在地应力场以及高压水下的起裂条件和起裂方向,给出了相应的计算方法。结合古书院矿15号煤的岩石力学参数和地应力场数据,计算出裂纹起裂压力17.6MPa,起裂角度12.8°。并且在古书院矿153303工作面进行了现场工业性实验,现场实际起裂压力与理论计算结果比较接近,从而验证了理论分析的可行性。
In order to study first fracture initiation situation and direction of hydraulic fracturing in underground, based on linear elastic fracture mechanics, round hole and wedge slot hydraulic fracturing crack mechanics model, the length of slot was almost equal to hole diameter, stress intensity factor of hydraulic fracturing crack tip was analyzed and calculated, according to crack tip stress inten-sity factor of slot, and the maximal circumferential tensile theory of composite fracture brittle fracture was used, the initiation situation and direction of fracture under underground stress and high pressure water were analyzed, then computing method was put forward. With rock mechanics parameters and underground stress data of 15 coal seam of Gushuyuan coal mine, the fracture initiation pressure was 17. 6MPa, initiation angle was 12. 8°. The results was applied in 153303 working face of Gushuyuan coal mine, the practical initi-ation pressure was almost equal to theoretical calculating results, the feasible of theoretical analysis was verified.
出处
《煤矿开采》
北大核心
2017年第1期11-14,30,共5页
Coal Mining Technology
基金
国家自然科学基金青年基金资助项目(51304119)
天地科技创新基金项目(KJ-2015-TDKC-15)
关键词
定向水力压裂
断裂力学模型
裂纹起裂条件和方向
最大环向拉应力理论
directional hydraulic fracturing
fracture mechanics model
fracture initiation situation and direction
the maximal cir-cumferential tensile theory
