基于土水特征曲线的渗流控制措施研究

利用WF非饱和应力路径三轴仪进行了壤土、砂壤土的土水特征曲线试验,结果表明: 2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。根据室内非饱和土的土水特征曲线试验结果,针对广阳水库蓄水后地下水抬升引起的地基土体由自然状态到非饱和状态到饱和状态这一变化过程,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环境工程地质条件的影响,并基于此分析论证了截渗沟这一渗控措施的对库区渗控效果的有效性。分析表明,设置截渗沟不但降低了地下水水位,而且也降低了地下水位以上土体内的含水量,这对减小浸没和次生盐碱化有实际的工程意义。

SEEPAGE CONTROL OF UNSATURATED SOIL BASED ON THE SWCC

This paper is based on the SWCC obtained from the test with the triaxial test instrument for unsaturated soils controlled by stress and strain(WF)in the laboratory.The test results show that the SWCCs of two kind of soils are different greatly.The state of the soil in the foundation under the reservoir changes form nature state to unsaturated state,and further to saturated state,because of the increase of water content after sluice of the reservoir.The change course of soil saturation is analysed with FEM for seepage of unsteady and unsaturated conditions.The laboratory test results are further used in the numerical analysis.The engineering geology is influenced greatly by the change course.It is found that the provision of cut seepage ditch can diminish the influence of the change course.From the analysis,the effect of the measure of seepage control can reduce the groundwater level and reduce the water content of the soils up the groundwater level.This is important to reduce immerge and salt-basify for the project.