中文摘要：

基于断裂力学理论,分别研究水压诱发的拉伸与剪切破坏特征。在水压诱发拉伸破坏方面,建立考虑井筒影响的地应力与水压耦合下的射孔尖端裂缝应力强度因子计算方程,推演该条件下拉剪复合应力状态下的断裂准则以及临界水压和启裂角的计算式。运用该方法从理论上分析了井筒周围存在对称的2条裂纹时,启裂水压和角度受射孔倾角、射孔长度、井筒半径及主应力差的影响。研究结果表明,依据推演的拉剪复合型断裂准则计算得到的射孔启裂水压和角度与试验结果吻合良好。参数分析表明：随着射孔长度或井筒半径的增加,临界水压减小。在水压诱发剪切破坏方面,则根据裂纹面的应力状态,分别推导裂纹处于压剪闭合状态和压剪不闭合状态下,水压诱发剪切破坏的断裂准则,并考虑非奇异应力对剪切断裂的影响,进一步推导压剪闭合应力状态下发生剪切破坏的临界水压计算公式。

英文摘要：

The tensile and shear failures of rock subjected to high water pressure were studied with the fracture mechanics. For the tensile failure caused by high water pressure,a method was proposed to calculate the stress intensity factors of two symmetric radial cracks emanating from a pressurized borehole. The fracture initiation criterion under the tensile-shear stress condition and the equations for the critical water pressure and the fracture initiation angle were derived. The influence of the perforation angle and length,the radius of the borehole and the difference of the principal stress on the critical water pressure and fracture initiation angle of two symmetrical cracks were analyzed according to the proposed method. The results show that the theoretical calculated critical water pressure and fracture initiation angle are in good agreement with the experimental results. The parameter analysis indicates that the critical water pressure decreases with the increase of the perforation length and the borehole radius. For the shear failure of rock subjected to high water pressure,the shear fracture criterion of both open and closed cracks under the compression-shear stress state was derived considering the effect of non-singular stress component. Finally,the explicit solution for critical water pressure of shear failure under the condition of compression-shear stress state was proposed.