地下水开采引发的土体变形对污染物迁移影响研究

Study on Impact from Soil Mass Deformation on Pollutant Migration Initiated by Groundwater Exploitation

地下水开采引发的土体变形对污染物迁移具有重要影响。结合地下水渗流理论、太沙基一维固结理论和溶质运移对流-弥散理论,建立了变形土体中污染物迁移三维耦合数值模型,考虑了孔隙度、渗透系数和水动力弥散系数随有效应力的动态变化。通过对实际案例进行模拟,分析了地下水开采引发的土体变形对污染物迁移规律的影响。结果表明,地下水位下降,土体有效应力增加,土体骨架压缩变形,使得孔隙度、渗透系数减小,导致水动力弥散系数增幅减小,从而延缓了污染物迁移的对流扩散过程。

The soil mass deformation initiated by groundwater exploitation has major impact on pollutant migration. Combined with groundwater seepage theory, Terzaghi one-dimensional consolidation theory and solute migration convection-dispersion theory have established a pollutant migration three-dimensional coupled numerical model in deformed soil mass, considered dynamic variation of porosity, permeability coefficient and hydrodynamic dispersion coefficient along with the effective stress. Through practical case studies carried out simulation, have analyzed impact from soil mass deformation on pollutant migration initiated by groundwater exploitation. The result has shown that along with groundwater level lowering down, soil mass effective stress increased, and soil mass framework compressively deformed. Thus caused porosity, permeability coefficient, and hydrodynamic dispersion coefficient amplification decreased. Accordingly, postponed pollutant migration convection and dispersion processes.