Abstract: This study aims to investigate the dynamic stress field during the process of rock failure. Firstly, physical model experiments were conducted to obtain the results of acoustic emission (AE) in the laboratory. According to the measured results, an equation was established for describing characteristics of the rock mesoscale damage based on the energy dissipation theory. Then this equation was implemented to FLAC3D software by using the FISH language. The improved equation can not only automatically search rock units within the damage scope of AE, but also weaken mechanical parameters of meso units. Finally, the relatively true rock fracture dynamic stress field was successfully acquired. The calculated results of rock failure stress field showed good agreement with the experimental results, which verified the rationality of mesoscale damage characterisation method. Simultaneously, the obtained dynamic rock fracturing stress field can not only explain the damage causes from the point view of rock mechanics, but also can predict the location of next rock failure. However, this method still has some limitations, and it needs for further explorations.

Key words: acoustic emission, stress field, FLAC3D numerical simulation, dynamical inversion