土壤水高矿化度对粉质黏土水力特性的影响

Effects of High-TDS Soil Water on Hydraulic Characteristics of Silty Clay

为获取高矿化度土壤水条件下的水力特征参数,并比较不同处理的影响,实验测定淡水、30、100及250g/L土壤水矿化度处理土样脱湿过程的水分特征曲线,并利用RETC软件进行模型参数拟合。结果表明,粉质黏土条件下,van Genuchten-Burdine模型可拟合各不同处理土壤水分特征曲线。各组实测曲线形态显示,在吸力较大阶段,当土壤水吸力增大到一定程度时含水率才发生变化,二者呈多值对应关系。TDS-30处理对应的残余体积含水率θr最大,α、n值最小,非饱和水力传导度K值衰减最快;中等大小孔隙的变化对非饱和水力传导度影响较为显著。研究成果可为深入开展矿化度潜水蒸发数值计算提供支持。

To obtain the hydraulic characteristic parameters of silty clay under high-TDS of soil water and compare the difference of different TDS treatments,four experiments with soil water of freshwater,30,100 and 250g/L（TDS-3,TDS-30,TDS-100 and TDS？250）were carried out.The soil water retention curves were obtained under the processing of losing water,and the RETC software including various models was used to fit them.The results showed that the van Genuchten-Burdine model was the only suitable model for fitting each water retention curve.However,the measured curves indicated multiple corresponding relations between water content and soil suction at the large suction stages.The water content changed only when the soil suction changed at a certain degree of each stage.For the silty clay,the TDS-30 treatment had the maximumθr（residual moisture content）,minimumαand n,and the largest attenuation degree of K,the hydraulic conductivity,and the changing of the median pore size had a significant influence on K value.The conclusions of this research can be used for the further numerical calculation of the high-TDS phreatic water evaporation.