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浅埋薄基岩工作面溃水溃砂模拟试验及影响因素分析

Simulation test of water and sand burst in shallow and thin bedrock face and analysis of influencing factors

  • 摘要: 针对榆神府矿区首层煤炭资源开采过程中在通过古冲沟区域时多次发生溃水溃砂灾害的问题,探究了古冲沟区域浅埋深、基岩薄、松散层厚且含水的工作面溃水溃砂灾害发生机理,利用自主研发的溃水溃砂启动测试仪实现了浅埋薄基岩厚松散含水层工作面溃水溃砂灾害过程的室内试验模拟。根据溃水溃砂灾害现场特征确定了水头高度、裂缝特征(裂缝大小和倾角)、砂土体厚度和密实度、黏土层厚度等6个溃水溃砂启动影响因素,基于正交试验原理设计并实施了25组水砂溃涌启动模拟试验,通过总结25组系列试验的试验特征得到了溃水溃砂灾害孕灾过程规律:渗水水量增大水变混水砂突涌。利用极差分析法定量研究了不同影响因素对溃水溃砂灾害启动的影响程度,得到了水头高度是影响溃水溃砂灾害发生的最主要因素,影响程度占比为37.5%,进而提出了采前疏放水是减少溃水溃砂灾害发生的有效措施。对比分析了不同水头高度条件下溃水溃砂灾害的孕灾与灾害特征,研究得到了灾害启动临界水力坡降与其他影响因素的数学关系,为溃水溃砂致灾机理的研究提供依据。溃水溃砂启动前松散含水层内部孔隙水压力突降的试验特征为现场灾害监测与预警提供了依据。

     

    Abstract: Aiming at the problem of multiple water and sand disasters in the ancient gully area during the mining process of the first layer of coal resources in the Yushenfu Mining Area, the problem of shallow buried depth, thin bedrock, thick loose layer and water in the ancient gully area was explored. The water and sand burst disaster mechanism of the working face, the self-developed water and sand burst start tester was used to realize the indoor test simulation of the water burst and sand burst disaster process of the shallow buried and thin bedrock thick loose aquifer. According to the site characteristics of the water and sand disaster, six factors affecting the initiation of water and sand burst, including water head height, the fracture characteristics (fracture size and inclination), the thickness and compactness of the sand body, and the thickness of the clay layer. The design was based on the principle of orthogonal experiment, and 25 sets of water-sand burst start-up simulation tests were carried out. By summarizing the test characteristics of 25 series of experiments, the law of the process of disasters caused by water and sand disasters was obtained: water seepage - water volume increase - water mixing - water sand sand bursts. The degree of influence of different influencing factors on the initiation of water and sand disasters was quantitatively studied by using the range analysis method. It is found that the height of the head is the most important factor affecting the occurrence of water and sand disasters, and the influence degree is 37.5%. Furthermore, it is proposed that draining water before mining is an effective measure to reduce the occurrence of water and sand disasters. A comparative analysis of the hazards and disaster characteristics of water burst and sand burst disasters under different water head heights was made, and the mathematical relationship between the critical hydraulic slope initiation of the disaster and other influencing factors was obtained, which provides a basis for the research on the mechanism of water and sand burst disaster.. The experimental characteristics of the pore water pressure drop in the loose aquifer before the start of water and sand burst provides a basis for on-site disaster monitoring and early warning.

     

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