基于最大周向拉应变断裂准则的岩石裂纹水力压裂研究  

Hydraulic fracture prediction theory based on the maximum tangential strain criterion

作　　者：唐世斌[1] 张恒[1] 

机构地区：[1]大连理工大学土木工程学院岩石破裂与失稳研究所,辽宁大连116024

出　　处：《岩石力学与工程学报》2016年第A01期2710-2719,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2014CB047100);国家自然科学基金资助项目(51474046);中央高校基本科研业务费专项资金资助(DUT14LK21)~~

摘　　要：通过对裂纹尖端应力场Williams展开式中非奇异应力项(T应力)的考虑,建立基于最大拉应变准则的岩石裂纹水力压裂的开裂判据,推导临界水压和起裂倾角的计算式。以此为依据计算水压致裂中的临界水压和临界偏转角的变化规律,分析裂隙倾角、围压、临界裂纹区尺寸、T应力、泊松比等因素对其影响作用。研究结果表明:随着围压、临界裂纹区半径以及泊松比的增加,起裂临界水压增大,临界偏转角逐渐减小。T应力对水压驱动型裂纹的扩展影响较小,但对外荷载作用下的裂纹扩展特征却有显著的影响。通过与试验结果的对比,考虑T应力的计算结果更为合理。A maximum tensile strain criterion is proposed to study the crack growth of hydraulic fracturing, which incorporates the effect of T-stress on crack growth. The critical water pressure and crack initiation angle at the onset of crack growth are studied. Furthermore, the effects of crack inclination angle, confining pressure, fracture process zone, T-stress and Poisson＇s ratio on the critical water pressure and crack initiation angle are also analyzed. The results show that the critical water pressure increases while crack initiation angle decreases with the increase of confining pressure, the radius of fracture process zone and Poisson＇s ratio. T-stress has little effect on propagation of fracture driven by water pressure. However, it is significantly effect on the propagation of crack driven by external loading. The theoretical results well agree with experimental data, which indicates the importance of considering the T-stress in the crack initiation criterion.

关 键 词：岩石力学 断裂力学 最大周向应变理论 水力压力 T应力 临界水压 

分 类 号：TU45[建筑科学—岩土工程]