基于氡气地表探测的覆岩采动裂隙及其含水性超前预报机理研究

Accurately and effectively monitoring the space-time dynamic evolution laws of mining-induced fractures field in overlying strata is the important basis of solving the three contradictions of coal resources mining and safety and environment disaster prevention in western mining areas of China. Aming at sovling the problems of high cost and the hardness of data accessing in the exisiting monitoring methods of mining-induced fractures and its aquosity, the method of radon radioactivity survey is introduced, and the quantitative analysis of the correlation between mining-induced fractures and its aquosity in overlying strata and radon concentration is taken to develop a new method of advanced prediction. Based on the typical geological conditions of Shenfu-Dongsheng coal mining area, the influence factors of radon separation in coal and strata at different positions are analyzed by experiment, based on which the mathematical model that accords with the mining and geological conditions is established to explore the laws of radon migration in mining-induced fractures medium of underground multilayer coal and strata. Based on these laws, the methods of numerical calculation and physical simulation are adopted to explore the advanced prediction mechanism of mining-induced fractures and its aquosity in overlying strata, and then the on-site experiments are used to test and perfect the theories. The research results could provide theoretical guidance and technical support for aquifer-protection mining in western mining area, mining-induced fractures partition, advanced prediction of roof breakage and deformation monitoring of mining surface.

准确有效地掌握覆岩采动裂隙场的时空动态演化规律及与上覆水体水力联系情况，是解决我国西部矿区煤炭资源开发与安全和环境灾害预防三者矛盾的重要理论基础。针对目前覆岩采动裂隙及其含水性的监测监控方法与手段存在成本高、数据获取困难等缺点，本项目拟通过引入氡气放射性测量方法，以覆岩采动裂隙及其含水性与氡气浓度之间的相关性定量研究为切入点，基于神府东胜矿区典型地质条件，实验分析地下不同层位煤岩层中氡气析出影响因子，进而建立符合采矿地质条件的氡气运移数理模型，探索地下多层煤岩层采动裂隙介质中氡气运移规律，在此基础上，采用物理模拟及数值计算手段，系统揭示基于氡气地表探测的覆岩采动裂隙及其含水性超前预报机理，并采用现场实证方法对上述研究成果进行验证和完善，以期初步形成一套氡气地表探测超前预报新方法。研究成果可为西部矿区保水开采、覆岩采动裂隙分区、顶板破断超前预报及地表移动变形监测等提供理论指导和技术支持。

西部煤炭资源的大规模开采，极易导致覆岩采动裂隙由下向上扩展直接与地表沟通，从而引发一系列安全与环境灾害，使潜在的生态环境脆弱性转化成为现实的破坏。因此，如何准确有效地掌握覆岩采动裂隙场的时空动态演化规律及与上覆水体水力联系情况，成为解决我国西部矿区煤炭资源开发与安全和环境灾害预防三者矛盾的重要理论基础。本项目立足上述矛盾，针对覆岩采动裂隙及其含水性的超前预报这一现实需求及现有监测监控方法和手段存在的不足，充分利用氡气特性，通过引入氡气地表探测的放射性测量方法，系统揭示了基于氡气地表探测的覆岩采动裂隙及其含水性超前预报机理，初步形成了一套简单易行又快速可靠的氡气地表探测超前预报新方法。主要研究内容包括：1）煤岩层地质组分与物理力学特性及氡气析出影响因子；2）地下多层煤岩层采动裂隙介质中氡气运移规律；3）基于氡气地表探测的覆岩采动裂隙及其含水性超前预报机理；4）氡气地表探测超前预报现场实证。最终取得了如下研究成果：1）界定了地下煤岩层介质晶格中氡原子的射气作用；2）研究了煤岩试件单轴压缩破坏过程中氡气析出浓度变化规律；3）建立了地下多层煤岩层介质中氡气运移数理模型；4）提出了一种地下不同层位煤岩层中氡气析出浓度原位测定方法；5）建立了氡气地表探测反演采动裂隙发育高度理论模型；6）提出了覆岩采动裂隙及其含水性氡气地表探测超前预报指标；7）验证了氡气地表探测覆岩采动裂隙及其含水性的可行性；8）构建了采场覆岩活动动态特征的“时空三位一体化”综合探测技术体系。研究成果可拓宽覆岩采动裂隙及其含水性的监测监控技术的新领域和氡气探测技术的应用范围，可为西部矿区保水开采、覆岩采动裂隙分区、顶板破断超前预报及地表移动变形监测等提供理论依据和技术支持。