The Influence of Loading Rate on Accumulated Energy Distribution in Coal–Rock Samples and Their Failure Behavior

The difference in energy accumulation in coal and rock under the same stress level is analyzed, and it is found that the difference of energy accumulation of coal rock under the same stress level mainly depends on the elastic modulus of coal rock material. Based on the structural characteristics and mechanical properties of coal–rock, the mechanical model of combined coal–rock body was constructed and analyzed, and the calculation formula of partition energy storage of combined coal–rock body was deduced. The axial compression test of combined coal–rock body under different loading rates was designed and carried out. Finally, the differential energy instability model of the combined coal–rock body was constructed. An evaluation index of the impact tendency of the combined coal–rock body considering the elastic energy difference and the release time is proposed, which provides a multi-scale criterion for accurately evaluating the impact propensity of the combined body.