Mesoscopic numerical simulation of acoustic emission experiment in rock compression failure under different confining pressures

The spatial and temporal distributions of acoustic emission(AE) during the deformation of granite samples containing an inhomogeneous fault were studied under confinement using particle flow code software(PFC2D).The results show that with the enhance of confining pressure,failure peak loads of rock samples increase and the failure mode changes from instability to gradual failure.The time asynchrony between AE peak values and ultimate failure in rock samples was found.The former which occurs when the failure load decreases approximately to 90% of its peak value is much later than the latter.Before rock failure there is a relatively quiet period of AE.AE temporal sequence is significantly affected by confining pressure and the relatively quiet period of AE may extend with the confining pressure increase.It is found that the phenomena of strain energy is absorbed during the relatively quiet period of AE through strain energy tracking,validating that damage healing exists in the rock failure process.