隧道开挖对地下水扰动影响与区域水运移规律分析

INFLUENCE OF TUNNEL EXCAVATION ON GROUNDWATER DISTURBANCE AND REGIONAL WATER TRANSPORT LAW ANALYSIS

通常隧道所穿越的山体地层复杂,受隧道开挖、环境变化和降雨情况等多种因素的影响,导致隧道周边出现地表水系断流、井水水位下降等问题。如何有效评价隧道贯通后围岩区域内地表水与地下水的关联特征,分析隧道开挖与地下水运移之间的关系,成为亟待解决的问题。基于此,采用无人机倾斜摄影测量技术拾取了地形地貌特征,实现了隧道区域内地形三维可视化;结合隧道工程地质勘察及开挖施工信息,构建了隧道施工区域内的三维裂隙网络模型,对隧道开挖后区域地下水非稳定渗流场进行模拟研究。结果表明,在地表水区域内存在三大流域,评估了各流域间真实单位面积的集水能力,量化了地表水径流固有的集水性能;基于渗流模拟表明,隧道修建对下游地下水的影响深度主要分布在40~90m。

The mountain stratum that the tunnel passes through is usually complex,which is affected by multiple factors such as tunnel excavation,environmental change and rainfall,leading to surface water system cut-off and well water level drop around the tunnel.How to effectively evaluate the correlation characteristics of surface water and groundwater in surrounding rock area after tunnel completion and analyze the relationship between tunnel excavation and groundwater migration has become an urgent problem to be solved.Based on this,the UAV tilt photogrammetry technology was used to pick up the topographic features and realize the three-dimensional visualization of the terrain in the tunnel area.Combined with the tunnel engineering geological investigation and excavation construction information,a three-dimensional fracture network model was constructed in the tunnel construction area,and the unstable seepage field of groundwater in the area after tunnel excavation was simulated,and the relationship between tunnel excavation and groundwater migration was analyzed.The results show that there are three major drainage basins in the surface water region,and the real water collection capacity of each basin is evaluated.Based on the seepage simulation,the influence depth of the tunnel construction on the downstream groundwater is mainly distributed in the range of 40~90 meters.