煤层采动顶板水文地质参数演化与矿井涌水量动态计算方法

Hydrogeological parameter evolution of coal seam roof and dynamic calculation method of mine water inflow

  • 摘要: 为预防煤矿采掘过程中突水事故的发生,开展矿井突水预测预报尤其是涌水量的精准计算尤为重要。以目前矿井涌水量计算普遍采用的解析法(也称“大井法”)为例,针对采动顶板水文地质参数演化与矿井涌水量动态精准计算之间的矛盾问题,在进一步分析笔者团队前期研究成果的基础上,阐述了采动顶板破坏过程中涌水形成机制和水文地质参数演化规律,探索性提出了变参条件下矿井涌水量动态计算方法,并进行了工程应用与可靠性评价。研究表明:采动诱发顶板直接充水含水层的渗透系数(K)呈“稳定增加—波动变化—恢复稳定”的变化特征,水位降深(S)和影响半径(R)呈“快速增加—略微下降—恢复稳定”的变化特征;传统解析法预计涌水量时在边界条件概化、参数选取以及计算过程存在误差,论文提出了矿井涌水量动态计算方法,即考虑采空区面积、水位漏斗动态变化过程的“移动大井”理论模型,以初次(周期)垮落步距为计算单元依次概化“移动大井”,渐次计算工作面推进过程中的动态涌水量;以徐矿集团下属某矿1306工作面为例,分别开展了工作面回采过程中引用影响半径(R0)单参数变化和引用影响半径(R0)、水位降深(S)双参数变化条件下的矿井涌水量动态计算,计算结果显示单参数和双参数变化条件下的矿井涌水动态计算方法可显著提高其计算精度,其相对误差平均值由传统解析法的140.7%可分别降低至88.7%、10.3%。研究成果可为矿井长期开采过程中干扰流场演化的推演,以及工作面回采过程中不同阶段矿井涌水量的动态、精准计算奠定方法基础,为矿井防治水工作开展和合理配备防排水设施提供依据。

     

    Abstract: It is particularly important to carry out water inrush prediction, especially the accurate prediction of mine water inflow in order to prevent the occurrence of water inrush disaster in the process of coal mining. The analytical method also known as “virtual large diameter well method”,which is widely used in the prediction of mine water inflow, is taken as an example. To overcome the contradiction between the evolution of hydrogeological parameters of mining roof and the dynamic and accurate calculation of mine water inflow, on the basis of further analysis of the authors' previous research, the formation mechanism of water inflow and the evolution law of hydrogeological parameters in the process of mining roof failure are described. The dynamic calculation method of mine water inflow under variable parameters is proposed, and the engineering application and reliability evaluation are carried out. The research shows that firstly, under the influence of roof mining failure, the hydraulic conductivity(K) is characterized by “stable increase-fluctuation change-restoration stability”,and the water table drawdown(S) and influence radius(R) are characterized by “rapid increase-slight decrease-restoration stability”. Secondly, the traditional analytical method has some errors in boundary condition generalization, parameter selection and calculation process when predicting water inflow. Subsequently, a dynamic calculation method of mine water inflow is proposed, which takes into account the “dynamic large diameter well” theoretical model of dynamic change process of goaf area and water table funnel. The first(periodic) caving step is used as the calculation unit to generalize the “dynamic large diameter well” in turn, and the dynamic water inflow during the mining activities is gradually calculated. Finally, taking the No.1306 mining panel of a mine affiliated to Xuzhou Mining Group as an example, the dynamic calculation of mine water inflow under the condition of single parameter change of the reference influence radius(R0) and double parameter change of the reference influence radius(R0) and water table drawdown(S) during the mining activities is carried out respectively. The calculation results show that the dynamic calculation method of mine water inflow under the condition of single parameter and double parameter changes can significantly improve the calculation accuracy, and the average relative error is reduced from 140.7% of the traditional analytical method to 88.7% and 10.3% respectively. The research results can lay a certain method foundation for the deduction of interference flow field evolution in the long-term mining process and the dynamic and accurate calculation of mine water inflow in different stages of mining activities, which can better guide the mine water prevention and control and reasonably equip the waterproof and drainage facilities.

     

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