Experimental Study on Damage and Failure of Coal-Pillar Dams in Coal Mine Underground Reservoir under Dynamic Load
Experimental Study on Damage and Failure of Coal-Pillar Dams in Coal Mine Underground Reservoir under Dynamic Load
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动载作用下煤矿地下水库煤柱坝破坏试验研究
DOI：
10.1155/2021/5623650
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发表时间：
2021-07
期刊：
影响因子：
1.7
通讯作者：
Qiang-ling Yao;Liqiang Yu;N. Chen;Weinan Wang;Qiang Xu
中科院分区：
文献类型：
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作者：
Qiang-ling Yao;Liqiang Yu;N. Chen;Weinan Wang;Qiang Xu
地下水利工程中煤柱坝的稳定性不仅受到长期水蚀的影响，而且还受到动载的影响，如顶板破裂或断层滑动等。通过无损浸泡试验研究了中国西部煤样的吸水特性，并用高速摄像机对不同含水率、不同应变率的煤样进行了SHPB试验监测。根据试验数据和实际工程条件，对煤柱坝进行了数值模拟。结果表明，在低应变率和高含水率条件下，压实阶段占应力应变曲线的大部分，而弹性阶段只占应力应变曲线的一小部分。动态抗压强度和弹性模量分别服从应变率的指数和对数函数，表现出显著的正相关关系。随着含水率的增加，动弹模数几乎呈线性增加，抗压强度逐渐降低。在相同的冲击载荷下，含水率越高的试件破坏越快，平行裂纹扩展为交错裂纹会加剧破坏。煤屑的平均粒径随应变速率和含水率的增加而线性减小。模拟结果表明，动载作用增加了坝体两侧的应力集中，扩大了高应力区和塑性区。研究结果为防水煤柱和地下水库坝的设计提供了指导。
The stability of coal-pillar dams in underground hydraulic engineering works is affected not only by long-term water erosion but also by dynamic loading induced, for example, by roof breaking or fault slipping. In this paper, the water absorption characteristics of coal samples from western China were studied by nondestructive immersion tests, and a high-speed camera was used to monitor SHPB tests on samples of varying water content and subjected to various strain rates. Besides, the coal-pillar dam is numerically simulated based on the experimental data and the actual engineering conditions. The results show that, given low strain rate and high water content, the compaction stage accounts for most of the stress-strain curve, whereas the elastic stage accounts for only a relatively small fraction of the stress-strain curve. The dynamic compressive strength and elastic modulus follow exponential and logarithmic functions of strain rate, respectively, exhibiting a significant positive correlation. As the water content increases, the dynamic elastic modulus increases almost linearly, and the compressive strength decreases gradually. Under the same impact load, samples with greater water content fail more rapidly, and the failure is exacerbated by the propagation of parallel cracks to staggered cracks. The average size of coal fragments decreases linearly with increasing strain rate and water content. Simulations indicate that dynamic loading increases the stress concentration on both sides of the dam and expands the high-stress area and plastic zone. The results provide guidance for designing waterproof coal pillars and underground reservoir dams.