Particle flow simulation of fracture characteristics and crack propagation mechanism of holed-cracked Brazilian disc specimen

Based on the experimental results of intact Brazilian disc of rock-like materials, a set of mecroscopic parameters in particle flow code (PFC) that can reflect the macroscopic mechanical behavior of rock-like materials under Brazilian test are obtained. Then PFC is used to simulate Brazilian test for holed-cracked Brazilian disc (HCBD) specimen. The effect of crack angle and radius ratio on the mechanical parameters of HCBD specimen is analyzed. Compared with intact specimen, the split load of HCBD specimen takes on a reducing tendency, and the reducing extent is closely related to pre-hole and crack parameters. The split load is non-linearly changed as crack angle increasing, but linearly decreases as the increase of radius ratio. In the range of simulation test, when the crack angle is smaller, the hole is the main reason resulting in the main crack initiation; while the crack angle is bigger, the reason of main crack initiation results from the pre-existing crack. When the crack angle is a constant and the radius is relatively smaller, the pre-existing crack is the main reason of main crack initiation; while the crack angle is bigger, the main crack initiation results from the pre-existing hole. Finally, the crack propagation mechanism of HCBD specimen is discussed.