Numerical study on the influence of rock bridge on failure process of flawed rock exposed to dynamic cyclic loading

The instability of rock mass in civil or mining engineering is always attributed to the coalescence of rock bridges among the intermittent joints. The aim of this work is to reveal the fracture mechanism of flawed rock mass influenced by the rock bridge segment. The numerical model is characterized with a flawed rock sample with two joints and rock bridge with different approach angle. Two-dimensional computational modelling studies have been used to try to understand how the fracture evolution responses affected by the approach angle of pre-flaws. The numerical results demonstrate that rock bridge segment influences the strength, crack propagation and acoustics emission responses, the acoustic emission (AE) events increase with the increase of approach angle. In addition, rock with strong bridge segment is different to failure and the two flaws are hard to be communicated, the amount of AE signal is less than rock with weak rock bridge segment.