基于变权的浅埋煤层顶板含水层富水性评价及其覆岩冒裂突水机理研究

Mining of shallow-buried coal seams is challenged with water inrushes from the roof aquifer in mines located in west China. Based on the existing research accomplishments, this project will combine the multi-source information fusion technology with the variable-weight approach to creatively and quantitatively determine the thematic maps and the variable weights for the main factors and to establish the prediction model of water abundance for the roof aquifer. Characterization of fractures of the overlying strata and its controlling factors will be analyzed by analog physical modeling to build the height calculation model of mining-induced hydraulic fracture zone. Based on the existing mechanical model of faults water inrush with fluid-solid coupling and with controlling factors of fractures determined by physical modeling, evolution process of fractures of overlying strata with different crack densities will be simulated under the same mining conditions. The nonlinear mechanical model of fracture water inrush with fluid-solid coupling will be built by continuously fitting numerical model.. Finally, the sufficient and necessary conditions and the specific engineering criterion will be proposed for the occurrence of water inrush through these fractures by coupling the height calculation model of mining-induced hydraulic fracture zone and the water abundance prediction model. The water inrush mechanism through fractures will be revealed by coupling the height calculation model of mining-induced hydraulic fracture zone, the water abundance prediction model and the nonlinear mechanical model of fracture water inrush with fluid-solid coupling.

针对西部矿区浅埋型煤层在开采过程中所面临的顶板水害难题，本项目在已有研究的基础上，采用基于变权的多源信息融合技术，创新性地定量确定不同主控因素专题图和影响富水性的变权权重，建立浅埋煤层顶板含水层富水性指数模型；通过物理模拟试验分析覆岩冒裂损伤的特征及其控制因素，构建导水裂隙带发育高度计算模型；以原有断层流固耦合滞后突水非线性力学模型为基础，数值模拟不同裂隙密度的覆岩，在相同采动条件下的冒裂演化过程，利用物理模拟确定的覆岩冒裂控制因素，不断拟合数值模型，并用现场导水裂隙带实测资料进行验证分析，构建覆岩冒裂突水流固耦合非线性力学模型。最后，通过耦合导水裂隙带高度计算模型和基于变权的含水层富水性指数模型，提出覆岩冒裂突水发生的充分必要条件和具体工程判据；通过耦合导水裂隙带高度计算模型、基于变权的含水层富水性指数模型及覆岩冒裂突水流固耦合非线性力学模型，揭示浅埋煤层覆岩冒裂突水的机理。

针对西部矿区浅埋型煤层在开采过程中所面临的顶板水害难题，本项目在已有研究的基础上，采用基于变权的多源信息融合技术，创新性地定量确定不同主控因素专题图和影响富水性的变权权重，建立了浅埋煤层顶板含水层富水性指数模型，不仅能确定不同评价指标的权重，而且能确定同一指标处于不同状态值时的不同权重；基于现场地表和井下钻孔开展了典型工作面采动条件下导水裂隙带高度实测，同时采用FLAC3D模拟工作面回采过程中导水裂隙带高度发育情况、围岩的破坏形态，采用UDEC模拟该工作面回采过程中覆岩垮落过程与形态，构建了导水裂隙带发育高度计算模型；最后，通过耦合导水裂隙带高度计算模型和基于变权的含水层富水性指数模型，提出了覆岩冒裂突水发生的充分必要条件和具体工程判据，并通过典型矿井的工程应用，揭示了浅埋煤层覆岩冒裂突水的机理。