西北矿区采动隔水层氡气运移机理与失稳预警方法

The stability of mining-induced aquiclude is the key to realize the aquifer-protection mining, and its essence is to protect the water-resisting property of the aquiclude, in order to protect the ecological environment systems from degradation in the mining areas. Aiming at the stability detection challenge of mining-induced aquiclude in the aquifer-protection mining process, introducing the method of radioactive radon survey, this project is conducted from the breakthrough point of the radon concentration variation characteristics during the process of mining-induced aquiclude instability. Based on the typical occurrence characteristics of shallow coal seams in northwest mining areas, from a quantitative perspective, the key influence factors and its weights of radon emission is determined, and the micro/macro features of radon emission in the typical coal and strata are analyzed by experiments. The mathematical model that accords with the mining and geological conditions is established to reveal the mechanisms of radon migration in mining-induced aquiclude (fissured medium). On this basis, the three-dimensional physical simulation and numerical calculation models are established, the quantitative relationship between the radon concentration variation characteristics and the deformation indexes of mining-induced aquiclude stability is determined, and the early warning criterion of mining-induced aquiclude instability is put forward, as well as the early warning method is finally founded. At last, the on-site tests are used to optimize and perfect the above theories. This project has a good scientific significance and research value, and the expected results could provide theoretical guidance and technical support for aquifer-protection mining and ecological environmental damage prevention in northwest mining areas.

采动隔水层的稳定性是实现保水采煤的关键，其实质是保护隔水层的隔水性能，以实现矿区生态环境系统不劣化。本项目针对保水采煤过程中采动隔水层的稳定性探测难题，拟通过引入氡气放射性测量方法，以采动隔水层变形失稳破坏过程中氡气浓度变化特征为切入点，基于西北矿区浅埋煤层典型赋存特征，从定量化角度出发，确定氡气析出关键影响因子及其所占的权重，实验分析矿区典型煤岩层中氡气析出的微/宏观特征；构建符合采矿地质条件的氡气运移数理模型，揭示采动隔水层（裂隙介质）中氡气运移机理；在此基础上，建立三维物理模拟及数值计算模型，确立采动隔水层稳定性的变形指标与氡气浓度变化特征之间的定量关系，提出采动隔水层失稳预警判据，最终建立基于氡气探测的采动隔水层失稳预警方法，并通过现场实证对上述研究成果进行优化和完善，具有较好的科学意义和研究价值。研究成果可为我国西北矿区保水采煤及生态环境损害防治等提供理论依据和技术支持。

采动隔水层的稳定性是实现保水采煤的关键，其实质是保护隔水层的隔水性能，以实现矿区生态环境系统不劣化。本项目针对保水采煤过程中采动隔水层的稳定性探测难题，通过引入氡气放射性测量方法，以采动隔水层变形失稳破坏过程中氡气浓度变化特征为切入点，深入研究了西北矿区采动隔水层氡气运移机理与失稳预警方法。本项目通过研究取得了如下主要成果：1）研制了气液增压加载煤/岩试件蠕变试验系统；2）测定了不同围压及含水率条件下弱胶结典型岩石力学性能参数；3）明确了典型煤岩层中氡气析出的内/外影响因素；4）掌握了典型煤岩破坏过程中氡气析出浓度变化特征；5）确定了典型煤岩层中氡气析出主要影响因素权重与氡气析出率；6）阐明了水作用下地下多层均匀多孔介质中氡气运移规律；7）开发了厚煤层下分层“混合顶板”完整性探测及其控制技术；8）研发了釆动覆岩固液耦合三维无损监测大型实验系统；9）系统掌握了弱胶结地层采动覆岩移动与导水裂隙发育动态演化规律；10）集成创新了保水开采“远-近-临”一体化监测预警方法。项目研究成果已在徐州矿务集团有限公司、伊犁新矿煤业有限责任公司、陕西煤业化工集团有限责任公司等单位下属的伊犁、库拜、天山、哈密、榆林、神木、神东、鄂尔多斯等8个矿区20余个矿山开展了初步应用，形成的技术成果通过中煤科工集团南京设计研究院有限公司在西北部矿井的规划、设计、改造过程中进行了初步推广，为相关矿井解决了脆弱生态区保水开采难题，取得了良好的经济效益和显著的环境效益。