Failure behaviour of rock-like materials containing two pre-existing unparallel flaws: an insight from particle flow modeling

Abstract

The paper presents a systematic numerical simulation of rock-like specimen containing two pre-existing unparallel flaws under uniaxial compression. The strength and deformation properties and crack evolution process of pre-flawed specimen are compared with the corresponding laboratory experimental results. The numerically simulated results, such as the axial stress–strain curve, the strength and deformation parameters, the ultimate failure mode and the crack coalescence process, were all in a good agreement with the experimental results, suggesting the validity of the calibrated micro mechanical parameters. The stress field during the crack coalescence process was analysed to reveal the mechanism of crack evolution. When the flaw angle was smaller or equal to 30°, the tensile stress concentration was distributed at the middle surface of pre-flaw. As the flaw angle increased, the tensile stress concentration was diverted from middle surface to the tips of pre-flaw. Finally, two typical displacement field types were defined to investigate the evolution of displacement vectors around the pre-existing flaws during loading. The numerically simulated results are expected to increase the understanding of fracture mechanism of rock-like specimens containing unparallel flaws.