范各庄矿井地下水系统广义多重介质渗流模型

GENERALIZED MULTIPLE POROUS MEDIA SEEPAGE MODEL OF GROUNDWATER SYSTEM FOR FANGEZHUANG MINE

为充分体现矿井裂隙水系统的强烈非均质性和不连续特征,运用广义多重介质理论,系统地研究了范各庄煤系含水介质。地质研究及水文地质试验表明,陷落柱作为含水介质的主干裂隙,其水文地质特征、渗流量计算等均不同于断裂裂隙或褶皱轴部裂隙,应概化为另一类主干裂隙介质;范各庄矿井地下水系统以煤层底板砂岩介质为主要目标含水层,F0断层及其伴生构造、井口向斜轴部、塔坨向斜轴部、13#陷落柱为主干裂隙,其间为等效裂隙岩块;主干裂隙控水且主干裂隙水流服从水流三次方定律,陷落柱等同水流管道,裂隙岩块等效多孔渗流介质;用水量交换耦合组成了广义三重介质渗流模型,该模型充分体现了煤系裂隙含水系统流场的空间特征,特别是强径流带和局部非连续渗流特征。广义三重介质渗流模型的流场和模型识别显示,范各庄矿井底板砂岩含水层正常裂隙岩块的渗透性及储水性较差,矿井水主要来源于构造导通的下部灰岩含水层;以不同矿井(突)涌水量为输入,运行系统模型,所得的流场形态分析认为,三水平12煤—14煤含水层的正常涌水量以0.167m3/s较为适当,最大涌水量不超过0.25m3/s,矿井正常总涌水量为0.333～0.417m3/s,矿井最大总涌水量为0.5m3/s。

For fully representing the characteristics of fractured rock masses, such as strong nonhomogeneity and discontinuousness, the media are studied with generalized multiple porous media theory. Geological research and hydrogeologic tests show that, as main fractures and vertical passageway of aquifer, karstic collapse columns have hydrogeologic characteristics and calculation mode of seepage rate different from that of joints in rock masses and should be generalized as another kind of main fractures. So, the groundwater system of Fangezhuang mine is simulated accurately by generalized multiple porous media seepage model in which fault F0, Jingkou syncline axis, Tatuo syncline axis and No. 13 karstic collapse column are main fractures, sandstone of coal floor is the target aquifer, equivalent porous media are among main fractures, and groundwater flow is mainly controlled by main fractures and obeys cubic law, karstic collapse columns work as water pipelines, and the fractured rock masses are equivalent to porous media. The model well represents dimensional characteristics of fractured system of groundwater, especially for the strong runoff zone and local discontinuous seepage. Water volume of colliery is forecasted with the model, and the results show that storage capacity and permeability of normal fractured rock masses in sandstone aquifer are poor, and the mining water in mine is mainly from sandstone aquifer recharged by Ordovician limestone with vertical passageways or fractures. By analyzing seepage fields and taking dewatering volume of the colliery as input, the stimulation results show that the natural volume and the largest volume of groundwater on the third mining level are 0.167 m3/s and 0.25 m3/s respectively, and the total natural volume and the largest total volume of groundwater of this mine are 0.333-0.417 m3/s and 0.5 m3/s respectively.