Effects of coal's initial macro-cracks on rockburst tendency of rock-coal composite samples
Effects of coal's initial macro-cracks on rockburst tendency of rock-coal composite samples
复制标题
煤体初始宏观裂纹对岩煤复合试样岩爆倾向的影响
DOI：
10.1098/rsos.181795
复制
发表时间：
2019-11-01
影响因子：
3.5
通讯作者：
Jiang, Ning
中科院分区：
文献类型：
--
作者：
Chen, Shaojie;Yin, Dawei;Jiang, Ning
通过砂岩-煤岩复合试样的单轴压缩试验，研究了煤岩中原始宏观裂隙对冲击倾向性的影响。首先，利用能量耗散理论推导了复合材料试样在单轴加载过程中的弹性能量衰减指数。在此基础上，利用单轴抗压强度和弹性能量衰减指数对复合试样的岩爆倾向性进行了评价和分析。结果表明，煤体中的原始宏观裂纹加剧了复合试样的冲击倾向性。原始水平裂纹对岩爆倾向的影响最小，而垂直穿透裂纹通过煤中心（平行于加载方向）显示出最大的效果。这些宏观裂纹削弱岩爆倾向的机制包括两个步骤：（i）改变复合试样的物理性质和能量积累条件;（ii）增加单轴加载过程中复合试样的能量耗散。这对认识深部开采过程中煤层-顶板复合系统的结构失稳破坏所引发的冲击地压灾害具有重要意义。
In the present study, uniaxial compression tests were conducted on sandstone-coal composite samples to investigate the effects of original macro-cracks in coal on the rockburst tendency. First, the energy dissipation theory was used to derive the elastic energy attenuation index of composite samples during uniaxial loading. Then, based on the test results obtained, the rockburst tendency of composite samples was evaluated and analysed using the uniaxial compressive strength and elastic energy attenuation index. The results show that the original macro-cracks in coal deteriorated the rockburst tendency of composite samples. The original horizontal cracks had the lowest effect on the rockburst tendency, whereas the vertical penetrating cracks through the coal centre (parallel to the loading direction) displayed the greatest effect. The mechanism by which these macro-cracks weakened the rockburst tendency involved two steps: (i) changing the physical properties and energy accumulation conditions of composite samples and (ii) increasing the energy dissipation of composite samples during uniaxial loading. These aspects are important to understand the rockburst hazards induced by the structural instability and failure of the composite system of coal seam and roof rock during deep coal mining.