Theoretical model for tensile and shear crack initiation at the crack tip in rock subjected to hydraulic pressure
TANG Shibin1，LIU Xiangjun2，LUO Jiang1，DONG Zhuo1
(1. Institute of Rock Instability and Seismicity Research，School of Civil Engineering，Dalian University of Technology，Dalian，Liaoning 116024，China；2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation，Southwest Petroleum University，Chengdu，Sichuan 610500，China)
Abstract：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.
唐世斌1，刘向君2，罗 江1，董 卓1. 水压诱发裂缝拉伸与剪切破裂的理论模型研究[J]. 岩石力学与工程学报, 2017, 36(9): 2124-2135.
TANG Shibin1，LIU Xiangjun2，LUO Jiang1，DONG Zhuo1. Theoretical model for tensile and shear crack initiation at the crack tip in rock subjected to hydraulic pressure. , 2017, 36(9): 2124-2135.
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2017, Vol. 36 
