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水压致裂的基本计算原理是以最大张应力准则为基础的。一般认为水压致裂过程中,孔壁在水压力的作用下只会发生拉张破坏。最近的实践表明,孔壁的破坏不仅会产生张性破坏还会产生剪切破坏。本文基于摩尔-库伦准则,通过理论推导得出水压致裂过程中孔壁不仅产生张性破坏,也产生剪切破坏,同时验证了摩尔-库伦准则在水压致裂孔壁破坏机理研究中的适用性;利用数值模拟的手段以莫尔-库伦准则来说明水压致裂应力测量中裂缝并不总是拉张破坏引起的,也有可能是剪切破坏,且起裂位置与应用最大拉应力准则时重合;由于围压对莫尔-库伦剪切破坏准则破裂应力有较大影响,因此即使同一种岩石在不同的应力状态下的破裂对应正应力也将不同,该研究为摩尔-库伦准则在水压致裂中的应用有重要的参考价值。
The basic principle of hydraulic fracturing is based on the principle of maximum tensile stress. Generally believed that the process of hydraulic fracturing, pore wall under tension in the water will only occur under tension damage. Recent practice shows that the failure of the cell walls not only produces tensile damage but also shear damage. Based on the Mohr-Coulomb criterion, the theory deduces that the pore wall not only produces tensile failure but also shear failure in the hydraulic fracturing process, and at the same time verifies the Mohr-Coulomb criterion in the study of the fracture mechanism of hydraulic fracturing wall Applicability; Numerical simulation method using Moore-Coulomb criterion to illustrate hydraulic fracturing stress measurement is not always caused by tension failure, it may be shear failure, and the location of initiation and application of the maximum tensile stress The coincidence of the normal stress with the same kind of rock depends on the Mohr-Coulomb shear stress. The Mohr-Coulomb criterion The application of hydraulic fracturing has important reference value.