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The hydraulic fracturing is one of common failure in hydraulic high water pressure tunnels. The process of hydraulic fracturing of high water pressure tunnel with different initial fracture length in tunnel inner wall is simulated using nonlinear FEM. The couple effect of fracture inner water pressure with surrounding rock mass deformation is considered in the model. The fracture propagation process with increasing of tunnel inner water pressure is analyzed, its effect on stress, displacement and plastic zone of tunnel surrounding rock mass is obtained. The results are compared with that obtained without considering existence of fracture water pressure. There are different results from two analysis method. The results show that only couple analysis can obtain relative authentic stress, displacement and plastic zone of tunnel surrounding rock mass, providing base data for correct stability assessment of surrounding rock mass.

Since the anisotropic characteristic of deformation and strength of layered rock masses, giving the reasonable constitutive model is of great significance for numerical analysis of the rock engineering concerned of layered rock masses. Based on the McLamore & Gray strength criterion, the isotropic Drucker-Prager strength criterion which is widely used in rock engineering is extended to be an anisotropic elastoplastic constitutive model for layered rock masses by making use of the conversion relationship between the Mohr-Coulomb strength criterion and the Drucker-Prager strength criterion. Then the presented anisotropic constitutive model is embedded in ABAQUS for its numerical implementation based on the derivation of the implicit integration algorithm and consistent tangent modulus. Numerical example is given for demonstration of the validity of the proposed constitutive model and its numerical implementation.