咸淡水驱替过程中含水介质渗透性变化的试验研究

摘要

在野外水文地质调查的基础上,采集青岛市大沽河下游咸水入侵区砂样,首先对含水介质的粒度和矿物组成进行了分析,然后通过室内砂槽模拟试验,对咸淡水驱替过程中含水介质的渗透性变化规律进行了研究.结果表明,当咸淡水相互驱替时,含水介质的渗透性会发生显著变化,这种变化主要是由于驱替液盐浓度的变化,使得伊利石、高岭石和绿泥石等非膨胀性粘土矿物经释放、迁移、絮凝和沉积,从而重新分布所引起的.含水介质渗透性的变化具有明显的非均质性,即位于距入水处不同水平距离以及不同高度处的含水介质,其渗透性变化规律有所不同.%Based on field geohydrological investigation, grain size and mineral compositions of the aquifer media collected from the downstream of Dagu River were analyzed. With sand tank laboratory experiment, the change law in hydraulic conductivity of aquifer medium in salt-freshwater displacement process was investigated. The result shows that there are significant changes in hydraulic conductivity of aquifer medium when the saltwater and freshwater displace each other. The reason for changes of hydraulic conductivity is that the migration, flocculation, sedimemt of released clay particles such as illite, kaolinite and chlorite ocur due to salinity changes. Changes in hydraulic conductivity are irregular. In various horizontal distances from water let and various heights, the change law in hydraulic conductivity of aquifer media is obviously different.