隔水层采动破坏裂隙的闭合机理研究及工程应用

煤层顶底板的采动裂隙是煤矿一系列灾害事故发生的根源,对其发育及演化规律的研究对各类灾害事故的防治具有重要意义。论文借助现场超声波成像技术、室内岩石矿物成分分析以及岩石膨胀性实验等手段,分析了影响煤层顶板采动裂隙闭合的相关因素,揭示了顶板隔水层采动裂隙的闭合规律。结果表明:顶板隔水层中的蒙脱石(包括伊/蒙混层)含量越高,其膨胀程度越大;隔水层距煤层顶板的距离越大,膨胀程度亦越大;在不发生顶板结构严重破坏的情况下,当隔水层的体积膨胀率大于采动裂隙的发育率,采动裂隙将实现有效闭合。最后,通过在新安煤田水体下采煤岩体渗透性评价以及神东矿区水资源保护性开采中的工程应用,对顶板采动裂隙的闭合机理进行了验证,并取得了良好的应用效果。

Closing Mechanism of Mining-Induced Fracture in Coal Mine Aquifuge and Its Application

The mining-induced fractures in roof and floor are the origin of a series of mine disasters.Thus,the research on the development and evolution law of the fractures has great significance to the mine disaster prevention.To study the closing mechanism of mining-induced fractures in overburden aquifuge and the associated influencing factors,several research means,including the ultrasonic imaging technology,mineral composition measurement and expansibility experiment are introduced in this paper.The results show that the expansion rate of the overburden aquifuge shows direct proportion to the montmorillonite content(including mixed minerals of Illite and montmorillonite) and its distance to the coal seam roof.Meanwhile,when the overburden structure is not suffered a severe damage,if the expansion rate is greater than the development rate of fracture,the mining-induced fracture can be closed effectively.Finally,the research result has been successfully verified by the penetrability evalution of coal mining under water body at Xin’an Coalfield and the water-preserved mining at Shendong Mining Area,and has achieved a good application effect in practice.