动载作用下岩-强/软阻隔层-煤组合承载体应力波传播衰减规律及能量耗散的特征

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

冲击地压应力波的主动衰减方法一直是煤炭巷道安全防治的重要研究难题。文章从不同强度的传播介质角度出发,提出岩-强/软阻隔层-煤的新型阻隔结构,采用动力冲击试验方法,分析煤岩体在阻隔层影响下的应力波传播衰减规律、能量耗散特征及表观破坏程度。研究结果表明,阻隔层能够对应力波波峰的表现形态产生影响,阻隔层强度越强,反射应力波波峰处的浮动震荡越明显,阻隔层强度越弱,透射应力波峰处浮动震荡越大,且出现明显的“双峰”现象;阻隔层能够降低应力波的循环“拉伸-压缩”频率,降低应力波破坏程度;强阻隔层影响下的煤岩体吸能能力提高约10%,软阻隔层可提高试样达到吸能峰值的速率。

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.