Abstract:
By material mechanics testing machine and acoustic emission signal detection and analysis system, the uniaxial compression acoustic emission tests under different loading rates of coal samples from Xiaojihan Coal Mine were accomplished and the acoustic emission characteristics curves of coal samples under the complete stress strain process were achieved and the changing laws of characteristic parameters such as ultimate strength, acoustic emission energy, ringing count with the different loading rates have been analyzed. The research shows that: with the increase of loading rate, the compressive strength and compression ratio of the coal samples show the trend of decreasing after the first rise, and the release form of acoustic emission energy for coal samples changes from the lone shock to swarm type, and under the lower loading rate, the energy release form is mainly solitary type and under the higher loading rate, the energy release form is mainly the swarm type; the change tendency of coal samples ringing counts is roughly same under different loading rates, which experienced a slow increase and fast increase stage, and with the increase of loading rate, the cumulative ringing counts of acoustic emission decreased significantly; the damage of coal sample in single axial compression is the single shear and double shear failure, and the three-dimensional positioning map of coal sample acoustic emission is in good agreement with the broken object.