Abstract: In the rock-like materials, two types of cracks can be observed when the specimens are subjected to compressive loads: tensile cracks and shear cracks. Peridynamics is a novel meshfree method used to solve the fracture problems. To simulate crack propagation of rock specimens under compression, Mohr-Coulomb criterion and maximum principal stress criterion are implemented into the non-ordinary state-based peridynamics, which are used respectively to simulate the shear failure and tensile failure of materials. The extended non-ordinary state-based peridynamics (ENSPD) is efficient for modelling the crack propagation and coalescence under complex loads. The program codes of ENSPD are compiled using Fortran 90. Firstly, the numerical simulation of a three-point bending test is regarded as a benchmark example to prove the accuracy of proposed method. The crack branching phenomenon under dynamic loads is modeled using ENSPD without any additional branching criterion and the present results are in good agreement with the previous experimental and other numerical results. A Brazilian disk of rock-like materials containing an inclined pre-exiting crack is then simulated. The predicted crack growth paths and the estimated fracture toughness well coincide with the previous experimental results. Finally, a rock-like specimen containing two coplanar pre-existing cracks under uniaxial compression is modeled using ENSPD. Compared with the experimental results, it can be found that the proposed numerical method has the ability to simulate and predict the initiation, propagation and coalescence of cracks in rock-like materials.

Key words: rock, peridynamics, crack propagation, crack coalescence, crack branching