Failure Mechanism and Acoustic Emission Characteristics of Coal–Rock Samples

In order to study the failure mechanism and acoustic emission characteristics of coal–rock combination with different coal-to-rock ratios, carry out uniaxial compression test and acoustic emission test on coal–rock combination with three coal–rock ratios of 1:2, 1:1, 2:1, start with parameters such as failure characteristics, stress-time curve, compressive strength, elastic modulus, acoustic emission events and energy counts, and analyze the failure characteristics, deformation characteristics and acoustic emission characteristics of the combined body. The result shows the following. The destruction of the coal–rock assembly occurs in the coal body, with the increase of the coal-to-rock ratio, the damage degree of the specimen gradually decreases, the broken shape gradually changes from broken and collapsed, and after tensile splitting, it becomes oblique shear failure. There is a phenomenon of "stress jump" and residual stress in coal-rock combination, after the stress reaches the peak, it jumps to the maximum value of residual stress, the larger the coal–rock ratio, the smaller the peak stress, but the residual stress is almost unchanged. The compressive strength and elastic modulus of the composite body decrease with the increase of coal-rock ratio, and the maximum axial strain increases with the increase of coal–rock ratio. Acoustic emission events and energy counts both showed stage changes that matched the stress–time curve. The energy counts and event counts at the same stage decreased as the coal–rock ratio increased.