煤层为主含水层开采中的防治水方法研究

A rarely unique water-bearing coal seam was found in Ordos Basin coalfield, China. The coal seam is characterized by large amounts of conductive fractures and is rich in water supply, which poses a great threat to coal resources extraction. The former existing controlling methods and techniques for water inrush from faults, karst zones, underlying and overlying layers, are no longer applicable to the aforementioned problem. Therefore, there is an urgent need to address this issue. In this proposed project, the fracture development and the corresponding seepage evolution in the water-bearing coal seam induced by mining operation in Hengyu coalfield will be comprehensively analyzed, via a combination method involving theoretic calculation, laboratory experiment, numerical simulation, physical similar simulation and in situ measurement. Then, a comprehensive model of working face water inrush will be built to reveal water inrush mechanism during mining operation. Further, a new comprehensive method using the drainage and decreasing pressure technology in high-position tunnel and the vertical drilling drainage technique will be proposed, in which the system layout for water drainage will be developed based on the in-situ mining and geological condition. Finally, the relation between the key technique parameters and in situ water level variations will be studied and used for the drainage system optimization. The research results in this proposed are expected to provide some scientific basis for mining in western China and some references for preventing water inrush in mines with similar conditions.

煤层为主含水层是我国鄂尔多斯盆地煤田内发现的一种极罕见的矿井水文地质结构，煤层中有大量贯通裂隙并富含水，采动过程中的矿井水主要来自本煤层，对矿井生产造成严重水害威胁。以往针对底板水、顶板水、断层水或岩溶水等的水害治理方法均不能直接适用于煤层为主含水层的水害防治。基于此，本课题以榆横矿区煤层为主含水层的开采条件为基础，采用理论分析、实验室测试、数值模拟、相似模拟和现场实测相结合的多种研究手段，通过分析采动煤层中的裂隙演化特征，揭示采动煤层中的渗流规律，建立采动煤层的涌/突水模型，从而揭示含水煤层在采动过程中的突水机理，提出高水高排与立体式钻孔法相结合的煤层水防治新方法，优化高水高排巷道和立体式钻孔布置系统，研究关键技术参数与煤层水量水位变化关系。这将为我国西部矿区高强度安全开采提供重要的科学依据，也为类似条件矿井水害防治提供重要技术手段。

鄂尔多斯盆地是我国重要的能源战略要地，区内含有丰富的优质煤炭资源。实践中，在鄂尔多斯盆地榆横矿区发现一种非常罕见的矿井水文地质构造，即煤层为主含水层。以往将煤层定义为隔水层，针对于底板水、顶板水、断层水或岩溶水等的保护“隔水层”治理方法，已不能适用于煤层为主含水层的水害防治。因此，研究煤层为主含水层开采中的防治水新方法，已成为煤层为主含水层矿井安全开采亟待解决的关键问题之一。. 基于此，本项目通过采用理论分析、实验室测试、数值模拟和现场试验等研究手段，研究了采动煤层中的裂隙演化与渗流规律、煤层为主含水层开采中的突水机理及采动煤层水的防治原理与方法等，取得以下主要研究成果：（1）采用实验室测试手段研究了含水煤层的内部原始结构特征及渗流特性，分析得到了含水煤层荷载作用下的应力应变本构关系。在此基础上，借助数值计算分析软件研究了煤层为主含水层在采动影响下的裂纹扩展与裂隙渗流规律，立体化展现了煤层为主含水层开采中的裂隙水流动变化特征。（2）采用物理相似模拟试验方法构建了煤层为主含水层开采中的流固两相耦合的涌突水模型，准确表达煤层为主含水层开采中的涌水规律呈现先降低后突增的变化趋势。基于数值模拟软件FLAC3D，分析与验证了采动煤层涌突水的动态演化规律。（3）在研究煤层为主含水层突水机理的基础上，提出两种针对煤层突水的防治方法包括采区煤层水的高水高排巷道卸压法和采场煤层立体式排水孔抽排法。为对煤层突水防治方法进行验证，构建采动煤层水动态监测方法并由监测数据显示煤层涌水量降至100m3/h以下，煤层水卸压至0.1MPa以下。. 通过项目研究形成煤层为主含水层防治水基本理论与技术体系，为西部矿区煤层为主含水层矿井高强度安全开采提供重要理论依据。项目成员在国内外高水平学术期刊上发表论文6篇，授权国家发明专利4项，编写软件著作权1项，获得省部级及企业科技奖励2项。