弱透水层压缩变形对溶质运移影响机理的实验和模拟研究

Correct understanding of the aquitard compression deformation mechanism and the solute transport processes in groundwater induced by compaction, is the basic study of effects of aquifer system compaction on groundwater geochemistry. Aquifer system compaction caused by deep groundwater overexploitation is highly related with aquitard compression, the storage release to aquifer and groundwater chemical composition changes. Coupled flow-solid and solute transport simulation studies concentrated in environmental and geotechnical engineering research field, but less in hydrogeology field. The project is to clarify cohesive soil compression mechanism and solute transport process on the basis of previous studies and theories, through physical simulation experiment and numerical simulation. The constructed coupled model is used to evaluate the solute transport under deformation conditions in regional conditions. The contribution of storage release related to aquitard compaction to deep groundwater pumping, and the impact of aquitard compaction on chemical compostion on groundwater in the aquifers is also to be assessed.

正确认识弱透水层压缩变形对地下水溶质运移的影响机理，是研究深层地下水超采造成含水层系统应力条件改变，粘性土弱透水层压缩释水，对相邻含水层水量和水质产生影响的基础工作。以往的流－固和溶质运移的耦合模拟研究多集中在环境岩土和工程岩土领域，在地下水资源域研究较少。本项目在前人研究的基础上，采用改装的三轴剪切渗透实验仪，采用溴粒子为渗透溶液离子，开展粘土层在不同受力及渗透梯度下的渗透实验和溶质运移物理模拟实验，建立土层压缩条件下的溶质运移耦合数值模型，阐明粘性土压缩对其中溶质运移过程的影响机理和模型参数关系。研究成果可为对地下水开采引发的弱透水层及含水砂层中粘性土夹层压缩释水对相邻含水层的水质影响提供科学参考。

正确认识弱透水层压缩变形对地下水溶质运移的影响机理，是研究深层地下水超采造成含水层系统应力条件改变，粘性土弱透水层压缩释水，对相邻含水层水量和水质产生影响的基础工作。本项目在前人研究的基础上，采用改装的三轴剪切渗透实验仪，采用溴粒子为渗透溶液离子，开展粘土层在不同受力及渗透梯度下的渗透实验和溶质运移物理模拟实验，建立土层压缩条件下的溶质运移耦合数值模型，建立典型多层含水层系统中粘土层压缩释水的数值模型。实验结果说明较高的渗透压和渗流速度条件下，渗流过程接近于达西流。多层含水层系统中粘土层压缩造成贮水系数减小，在一定孔隙水压力降低的情况下，粘土层和砂层能够给出的水量都会减少。研究成果弱透水层压缩释水对含水层系统影响提供科学参考。