Stress wave propagation attenuation law and energy dissipation characteristics of rock-barrier-coal composite specimen under dynamic load

The active attenuation method of rockburst stress wave is an important research problem in coal roadway safety control. In this study, the strengths of different propagation media were analyzed and a new type of coal-rock barrier test structure was proposed. The split Hopkinson pressure bar (SHPB) was used to analyze the propagation attenuation law of stress wave, energy dissipation characteristics, and apparent failure degree of coal and rock mass under the influence of barrier layer. The results show that the barrier layer affected the shape of the stress wave peak. The strength of the barrier layer affected the floating oscillation with stronger and weaker barrier layers, resulting in more evident floating oscillation at the reflection and transmission stress wave peaks, respectively. Additionally, an apparent “double peak” was observed for the weaker barrier layers. The barrier layer reduced the frequency of stress wave cycle “stretching and compression”, and ultimately the destructive force of stress wave. Under the influence of the strong barrier layer, the energy absorption capacity of coal and rock mass increased by approximately 10%, while the soft barrier layer accelerated the speed at which the samples reached peak energy absorption.