Fracture Modes of Single-Flawed Rock-Like Material Plates Subjected to Dynamic Compression

Knowledge of fracture process is critical for understanding rock failure mechanisms. In this study, the fracture behavior of single-flawed rock-like material plates made of mortar was investigated using a Split Hopkinson Pressure Bar (SHPB) system. The transient fracture process was recorded by an ultra-high-speed camera system in combination with the digital image correlation (DIC) method. The experimental result reveals that the dynamic strength is more sensitive to the loading rate for specimens with lower flaw angles. Through quantitative analysis of the displacement evolution along the fracture trajectory, four fracture modes were proposed: pure tensile mode (T-mode), pure shear mode (S-mode), tensile dominated mode (Ts-mode), and shear-dominated mode (St-mode). Moreover, it was recognized that the fracture mode is mainly controlled by the fracture angle. As the fracture angle increases, the shear component increases while the tension component diminishes. The results of this study can shed light on the fracture behavior of flawed rocks subjected to dynamic loading.