Experimental and numerical investigation on the failure behavior of far-field-crack-tunnel rock mass under dynamic loads

Multitudinous natural human-induced flaws exist in the rock mass, which could pose potential risks to the safety of tunnel engineering. To study the dynamic failure properties of the tunnel with a crack in the surrounding rock mass, a series of typical split Hopkinson pressure bar (SHPB) dynamic fracture tests were conducted. A highspeed camera was utilized to record the failure process and digital image correlation (DIC) techniques were applied to analyze the evolution law of strain field in the surrounding rock mass. Numerical simulations were performed using LS-DYNA software after calibrating the parameters of the Riedel-Hiermaier-Thoma (RHT) model. The findings of this study indicate that far-field cracks could contribute to tensile crack propagation from the tunnel vault and tunnel floor. In addition, simulations are highly consistent with model experiments, which proves its practicability and accuracy. These results could provide significant references for more secure, economical and efficient support solutions for engineering. The study also promotes the application of the RHT model to the dynamic response behavior of defected rock-like materials.