水库蓄水引发的地下水位抬升和渗控措施研究

Seepage control of unsaturated soil based on the SWCC

针对广阳水库蓄水后地下水抬升引起的周边土体由自然非饱和状到饱和状态这一变化过程,基于壤土、砂壤土的室内土水特征曲线试验结果,采用非饱和非稳定渗流有限单元法系统地分析了这一变化过程对库区周边工程地质条件的影响,论证了截渗沟对库区堤外防渗和渗控的有效性。利用WF非饱和应力路径三轴仪进行的壤土、砂壤土的土水特征曲线试验结果表明两种土体的土水特征曲线差别较大,基质吸力随含水量的变化呈现不一致性。非饱和非稳定渗流有限单元法计算分析结果表明截渗沟避免了坝后土层内浸润线大幅度提高,同时也避免了浸润线上部非饱和土体的含水量的大幅度增加,这可以减小次生盐碱化和浸没等问题的影响。

The change course of the soil in the foundation under the reservoir will change from natural state to unsaturated state to saturated state because of the increase of water content after sluice of the reservoir.The change course has been analyzed with the FEM of unstable and unsaturated base on the results in the lab.The engineering geology is influenced greatly by the course.The effect of the cut seep dyke can minish the influence of the change course.Based on the SWCC obtained from the test data with the triaxial test instrument for unsaturated soils controlled by stress and strain（WF） in the laboratory,the result of the test show that the SWCC of two kinds of soil are greatly different.The results of computation show that the measurements of seepage control can avoid the increase in the elevation of soakage and the water content of the soils,which is important to the environment of the reservoir.