Failure characteristic and acoustic emission spatio‐temporal evolution of coal under different cyclic loading rates

The coal and rock dynamic disasters occur more frequently in deep mining, which is tightly correlated to the instability of pillars under high stress cyclic disturbance load. In this study, strength, deformation behaviors, failure mechanism loading a high-stress state were investigated by considering influence rate. experimental results indicate that compressive strength positively with rate, patterns, AE amplitude, spatial evolution are same various rates. damage variable shows “slow increase→fast increase→slow increase→ fast increase →slow increase→rapid increase” trend. growth rate ranges from 9.32 × 10−5 4.86 10−3, increases fractal dimensions rates same, distribution 2.1 2.9, showing general downward microfailure mixed dominated tensile failure, small amount shear failure. There positive correlation between percentage cracks