Experimental study and particle flow modeling on 3D cracking behavior of rock-like samples with an embedded flaw

Cracking behavior of surface cracks in rock materials is extensively studied, while studies on cracking behavior of internal cracks are very limited. In this study, a new method for preparing rock-like materials containing embedded flaws is proposed using camphor sheets. A series of laboratory uniaxial and triaxial compression experiments were carried out on rock-like samples containing internal flaws. The experimental results demonstrate that the existence of an internal flaw results in a large reduction of the sample peak strength and elastic modulus. As the flaw inclination angle increases, the peak strength of flawed sample decreases, and the failure mode varies from the combined shear-tension failure to shear failure and then to splitting failure. Three 3D wing cracking patterns, which mainly occur in small flaw inclination angles, and one 3D shear cracking pattern, which mainly occurs in larger flaw inclination angles, are identified in the experiment. And then PFC3D was used to simulate cracking behavior of rock-like samples with internal flaws, and the simulated results (including stress–strain curve and failure modes) are in good agreement with the experimental results. The crack evolution mechanism in rock-like samples containing internal flaws is revealed by analyzing micro-crack propagation, contact force chain, and displacement field.