Rockburst prediction for deep tunneling near fault based on the PD-BEM method

A multiscale model coupling the peridynamic (PD) and boundary element method (BEM) is proposed to analyze the rockburst in deep tunnels near fault. The entire rockburst processes of the rock masses around the opening are captured by PD while the field conditions and boundary are described by BEM, which can take full advantage of their salient features and model the rockburst problems efficiently. The proposed model is verified by comparing its predictions with those from the field observations in "11.28" rockburst at the Jinping II Hydropower Station in China. Parametric analysis considering the dip angle and location of the fault as well as the ground stress is performed to reveal the rockburst mechanism of deep tunnel near fault. Numerical results indicate that the rockburst intensity of rock tunnel is a function of the distance between the fault and tunnel, the dip angle of fault and ground stress. Different failure modes, including buckling failure, slip failure and local slabbing failure are found in the simulation, which are controlled by the fault near the tunnel. Moreover, a new index for rockburst is proposed to predict the tendency and intensity of rockburst associated with deep tunneling near a fault.