杨科, 刘文杰, 马衍坤, 窦礼同, 刘帅, 魏祯, 许日杰. 煤岩组合体冲击动力学特征试验研究[J]. 煤炭学报, 2022, 47(7): 2569-2581.
引用本文: 杨科, 刘文杰, 马衍坤, 窦礼同, 刘帅, 魏祯, 许日杰. 煤岩组合体冲击动力学特征试验研究[J]. 煤炭学报, 2022, 47(7): 2569-2581.
YANG Ke, LIU Wenjie, MA Yankun, DOU Litong, LIU Shuai, WEI Zhen, XU Rijie. Experimental research on dynamic characteristics of coalrock combined specimen[J]. Journal of China Coal Society, 2022, 47(7): 2569-2581.
Citation: YANG Ke, LIU Wenjie, MA Yankun, DOU Litong, LIU Shuai, WEI Zhen, XU Rijie. Experimental research on dynamic characteristics of coalrock combined specimen[J]. Journal of China Coal Society, 2022, 47(7): 2569-2581.

煤岩组合体冲击动力学特征试验研究

Experimental research on dynamic characteristics of coalrock combined specimen

  • 摘要: 为探究冲击荷载作用下煤岩组合体承载结构的动力学响应特征,采用分离式霍普金森压 杆(SHPB)试验系统结合超高速摄像机,设计开展了4种典型岩样与相同煤样水平层状复合而形 成的煤岩组合体冲击压缩试验,对比分析了应力波由岩入煤情况下,煤岩组合体应力波传播规律、 动态应力-应变关系、能量耗散规律及破坏失稳特征。 研究结果表明:1.煤岩组合体与入射杆波阻 抗匹配效果的差异性对应力波传播的影响随冲击速度的增大逐渐减弱。 2 随冲击速度的增大,煤 岩组合体最大动态峰值应力和峰值应变具有明显的应变率效应,入射能呈线性增大且与试样无关, 反射能占比近似呈线性降低,最大动态峰值应力和吸收能占比近似呈幂函数增大。 3 冲击荷载作用下,煤岩组合体宏观裂隙起裂大多发生在远离煤岩交界面且强度相对较低的煤体或岩石端部,当 裂隙发育至煤岩界面处,且裂纹尖端应力大于“ 弱化” 煤岩强度时,裂隙将越过煤岩界面继续发育。4 煤岩组合体冲击破坏时,在组合体动力显现影响程度方面,呈现出冲击速度大于岩石强度,岩石 强度大于波阻抗匹配效果的规律。5 相同冲击速度下,随着岩石强度的增大,岩组分更多起到能 量的积聚和传递作用,岩石模式由劈裂破坏向剪切破坏转变,煤岩组合体动力显现逐渐向煤体转 移,煤体破坏程度逐渐增大,煤样破碎颗粒逐渐由块状向粉状过渡,煤样破碎块体块度平均粒径降 低,煤岩组合体分形维数逐渐增大。 研究结果对动压巷道围岩控制提供了基础研究。

     

    Abstract: To explore the dynamic mechanical characteristics of the bearing structure of the coalrock combined body, a separated Hopkinson pressure bar (SHPB) test device combined with an ultrahighspeed camera system was used to carry out the impact compression test on the coalrock combined body formed by the layered combination of four different rock samples and the same coal sample. The stress wave propagation, dynamic stressstrain relationship, dynamic evolution of cracks, energy dissipation law, and failure characteristics of the coalrock combined body in the case of stress waves entering coal from the rock were compared and analyzed. The results show that the influence of the difference in the wave impedance matching effect between the rock and the incident bar on the propagation of the stress wave gradually weakens with the increase of the impact velocity. The maximum dynamic peak stress and strain of the coalrock combined body have obvious strainrate effects. Besides, with increased impact velocity, the incident energy increases linearly, the reflected energy proportion decreases linearly, and the absorbed energy proportion and the growth rate of the maximum dynamic peak stress gradually drop, changing approximately as a power function. Most of the destruction of macroscopic cracks in the coalrock combined body occur at the coal or rock ends with relatively low strength and far away from the coalrock interface. When the crack tip stress at the coalrock interface is greater than the strength of “weakened” coal or rock, the cracks will cross the coalrock interface and continue to develop. When the coalrock combined body is damaged by impact loading, the impact velocity influence on the degree of breakage of the sample is greater than rock strength influence and the rock strength effect is greater than the wave impedance matching effect on the degree of breakage of the sample. Under the same stress wave, as the strength of the rock increases, the failure degree of coal gradually increases, the broken particles gradually transition from massive to powder and the rock mode changes from splitting failure to shear failure. As a result, the average particle size of broken coal blocks decreases, and the fractal dimension of coalrock combined body increases gradually. The research results provide basic research for the control of surrounding rock of roadway under dynamic pressure.

     

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