Coal seams are often affected by gas effects in addition to static and dynamic superimposed loads in the process of coal mining. Understanding the mechanical properties and energy dissipation of impacted coal under different initial gas pressures is extremely important. Therefore, dynamic compression experimentation of coal samples was conducted using a self-developed observable combined dynamic and static loading test system of gas-bearing coal. Furthermore, based on the crack volume increment, the crack energy dissipation density (CEDD) was defined to measure the energy required for a unit volume of cracks under different gas pressures, and the following conclusions were drawn: the deformation of gas-bearing coal can be divided into the elastic stage, elastic‒plastic stage, plastic stage and failure stage, and the dynamic strength and secant modulus decrease with increasing initial gas pressure. The impacted coal contains annular parallel cracks that run through the cross section and axial splitting/thoroughgoing cracks, and the two forms of cracks become more obvious with increasing initial gas pressure. The reflected energy of gas-bearing coal increases and the transmitted energy, dissipated energy and energy dissipation ratio decrease with increasing gas pressure. In addition, the CEDD decreases with increasing gas pressure because free gas and desorbed gas participate in external expansion work at the moment of impact, which results in a decrease in the CEDD required for gas-bearing coal failure. These conclusions enrich the basic theory of the dynamic coal–rock–gas disaster induction mechanism and can provide theoretical support for the monitoring, early warning and prevention technology of dynamic disasters in composites.

煤层在采煤过程中除静、动叠加载荷外，还经常受到瓦斯效应的影响。了解不同初始气体压力下冲击煤的力学性能和能量耗散非常重要。为此，采用自主研发的含气煤可观测动静联合加载试验系统，对煤样进行动态压缩试验。此外，基于裂缝体积增量，定义裂缝能量耗散密度（CEDD）来衡量不同瓦斯压力下单位体积裂缝所需的能量，并得出以下结论：含气煤的变形可以分为弹性阶段、弹塑性阶段、塑性阶段和破坏阶段，动态强度和正割模量随着初始气体压力的增加而降低。受冲击煤体含有贯穿横截面的环状平行裂纹和轴向劈裂/贯通裂纹，随着初始瓦斯压力的增加，两种裂纹形式更加明显。随着瓦斯压力的增加，含气煤的反射能增加，透射能、耗散能和耗能比降低。此外，CEDD随着瓦斯压力的增加而减小，因为游离气和解吸气在冲击瞬间参与外膨胀功，导致含气煤破坏所需的CEDD减小。