Abstract:The study of coal burst liability plays a key role in exploring the formation mechanism of rock burst during deep underground coal mining. In order to explore the influence of CO2 at different pressures on coal bursting liability, uniaxial compression and cyclic loading and unloading tests with variable upper limit were carried out on coal specimens after CO2 immersion at different forces. The test results show that: The uniaxial compressive strength of coal specimens decreased by 9.97%, 16.14%, 25.02%, 45.97% and 52.77% respectively after being treated with CO2 at pressures of 2 MPa, 4 MPa, 6 MPa, 8 MPa and 10 MPa. The elastic modulus decreased by 11.01%, 18.35%, 27.52% and 44.95%, respectively. With the increase of CO2 soaking pressure, the deterioration degree of mechanical properties of coal samples is gradually aggravated, and the total number of AE cumulative events decreases, which explains the damage mechanism of CO2 to coal body from the micro level. There is a linear relationship between the input energy Unin and the elastic energy Une in the process of cyclic loading and unloading with variable upper limit after CO2 immersion at different pressures. Compared with the original coal specimen, the residual elastic energy index CEF decreased by 9.35%, 17.16%, 25.54%, 47.18% and 55.48%, respectively, after the effect of CO2 at pressures of 2 MPa, 4 MPa, 6 MPa, 8 MPa and 10 MPa, indicating that CO2 has a weakening effect on the coal bursting tendency. When CO2 reaches its supercritical state, the effect on reducing the bursting liability of coal is more obvious.