Zheng Lulin, Wang Xiaokun, Lan Hong, Ren Weide, Tian Youwen, Xu Jin, Tian Shiyu
Mining College, Guizhou University, Guiyang, 550025, China.
Guizhou Lindong Coal Industry Development Co., Ltd. Longfeng Coal Mine, Jinsha, 551800, Guizhou, China.
Sci Rep. 2024 Sep 6;14(1):20790. doi: 10.1038/s41598-024-71853-x.
The hydrogeological conditions of the Qianbei coalfield are complex, and karst water in the roof rock frequently disrupts mining operations, leading to frequent water inrush incidents. Taking the representative Longfeng Coal Mine as a case study, research was conducted on the development pattern of the water-conducting fracture zone and the water inrush mechanisms beneath karst aquifers. On the basis of key stratum theory and calculations of the stratum stretching rate, the karst aquifer in the Changxing Formation was identified as the primary key stratum. It was deduced that the water-conducting fracture zone would develop into the karst aquifer, indicating a risk of roof water inrush at the working face. Numerical simulations were used to study the stress field, displacement field, and plastic zone distribution patterns in the overlying roof strata. Combined with similar simulation tests and digital speckle experiments, the spatiotemporal evolution characteristics of the water-conducting fracture zone were investigated. During the coal mining process, the water-conducting fracture zone will exhibit a "step-type" development characteristic, with the fracture morphology evolving from vertical to horizontal. Near the goaf boundary, the strain gradually decreases, and the instability of the primary key stratum significantly impacts the mining space below, leading to the closure of interlayer voids or the redistribution of water-conducting fissure patterns. Field measurements of the water-conducting fracture zone reveal that postmining roof fractures can be classified into tensile-shear, throughgoing, and discrete types, with decreasing water-conducting capacity in that order, the measured development height of the water-conducting fracture zone (51 m) aligns closely with the theoretical height (51.37 m) and the numerical simulation height (49.17 m). Finally, from the perspective of key stratum instability, the disaster mechanisms of dynamic water inrush and hydrostatic pressure water inrush beneath the karst aquifers in the northern Guizhou coalfield were revealed. The findings provide valuable insights for water prevention and control efforts in the Qianbei coalfield mining area.
黔北煤田水文地质条件复杂，顶板岩层岩溶水频繁干扰采矿作业，导致突水事故频发。以具有代表性的龙凤煤矿为例，对导水裂隙带发育规律及岩溶含水层下的突水机制进行了研究。基于关键层理论和地层拉伸率计算，确定长兴组岩溶含水层为主要关键层。推断导水裂隙带将发育至岩溶含水层，表明工作面存在顶板突水风险。采用数值模拟研究了上覆顶板岩层的应力场、位移场和塑性区分布规律。结合相似模拟试验和数字散斑试验，研究了导水裂隙带的时空演化特征。在采煤过程中，导水裂隙带将呈现“台阶式”发育特征，裂隙形态由垂直向水平演化。在采空区边界附近，应变逐渐减小，主要关键层的失稳对下方采矿空间有显著影响，导致层间空隙闭合或导水裂隙格局重新分布。对导水裂隙带的现场实测表明，采后顶板裂隙可分为拉剪型、贯穿型和离散型，导水能力依次降低，实测导水裂隙带发育高度（51米）与理论高度（51.37米）和数值模拟高度（49.17米）吻合较好。最后，从关键层失稳角度揭示了黔北煤田岩溶含水层下动水突水和静水压力突水的灾害机制。研究结果为黔北煤田矿区的防治水工作提供了有价值的参考。
