群矿开采条件下山西潞安矿区的地下水流场变化

摘要

Multiple coal mining leads to regional aquifer structure damage, which has seriously affected the regional groundwater circulation and evolution trend and seems to be the root cause of groundwater resource shortage in the coal mining area. With the Lu'an mining area in Changzhi basin as an example and through field investigation, similar material simulation and numerical simulation method, the authors analyzed the damage of aquifer structure and its influence on groundwater circulation. Sand tank simulation test results were compared with the results of numerical simulation, and the results show that the fissure development formed by coal mining is basically restricted to complete bedrock, which causes bending deformation of the water bottom clay rock and forms interlayer drainage area, but this has little damage to Quaternary unconfined aquifer structure; Effective thickness of thinner parts of water-resisting layer leads to the disappearance of unconfined aquifer due to mining fissures cutting waterproof layers; Artificial "headward erosion" caused by coal mining causes the abstraction phenomenon of groundwater between the original isolation groundwater systems, and mine water recharge appropriately increases.%煤炭开采导致区域含水层结构破坏, 已经严重影响了区域地下水循环演化态势, 是煤矿区地下水资源短缺的根本原因.本文以山西长治盆地潞安矿区为例, 通过野外调查、相似材料模拟实验和数值模拟手段, 分析了群矿开采驱动下含水层结构破坏对地下水流场的影响.通过砂槽模拟试验结果和数值模拟结果进行对比验证, 结果表明: 1)煤层开采形成采动裂隙发育基本限制在完整基岩内, 使得隔水底板黏土岩发生弯曲变形, 承压含水层水位下降形成层间疏干区, 对第四系潜水含水层流场影响甚微, 潜水水位没有明显下降; 2)隔水层有效厚度变薄的局部地区, 由于采动裂隙切穿隔水层, 导致该区潜水含水层消失; 3)采煤造成的类似"溯源侵蚀", 引发原本隔离的地下水系统间的地下水袭夺现象, 矿井水补给量有所增加.