中文摘要：

非饱和土土水特征曲线（SWCC）在非饱和土性质的研究中是很重要的。通过现场原位渗水试验、室内试验,结合数值反演得到了晚更新世黄土（Q3黄土）脱湿和吸湿土水特征曲线。用压力板仪测量Q3黄土脱湿过程中不同含水率下的吸力,之后用Van Genuchten经验公式对试验数据进行拟合,得出了Q3黄土脱湿SWCC曲线的数学表达式。在现场渗水试验的基础上,用随机搜索和经验逼近相结合的方法,通过数值计算反演Q3黄土吸湿过程中的土水特征曲线参数。此外,还实测了Q3黄土竖直向的饱和渗透系数。结果表明：Q3黄土脱湿路径的进气值为4.16 k Pa,饱和体积含水量为0.52;吸湿路径的进气值为3.92 k Pa,饱和体积含水量为0.48。残余体积含水量为0.01,残余饱和度为2.0%,残余的气体含量为4.06%。竖直与水平向渗透系数的比率为1.62,水平向饱和渗透系数为7.08＊10-6m/s,竖直向饱和渗透系数为1.147＊10-5m/s。室内实测竖直方向饱和渗透系数为2.71＊10-5m/s,反演值与实测值是属于同一数量级的。

英文摘要：

Soil-Water Characteristic Curve（SWCC） is very important in the research of the properties of the unsaturated soil. The SWCCs of Q3 loess in the desorption process and absorption process were obtained through the field infiltration test, indoor tests and numerical back analysis. The matrix suctions of Q3 loess in different water contents during the process of desorption water were obtained by the pressure plate extractor,and the SWCC was simulated with the Van Genuchten＇ s three-parameter model. Based on the field infiltration test, obtained the SWCC parameters of Q3 loess in the process of absorption water by the method of the numerical back analysis. In addition, the hydraulic conductivity in the vertical direction was measured. The results show that the air-entry value of Q3 loess in the desorption curve is 4. 16 kPa, and the saturated volumetric water content is 0.52. The air-entry value is 3.92 kPa in absorption curve, and the saturated volume water content is 0. 48. The residual water content is 0.01 ,the residual degree of saturation is 2. 0% ,and the residual air content is 4. 06%. The ratio of the hydraulic conductivity in the vertical direction to the horizontal direction is 1.62. The saturated hydraulic conductivity in the horizontal direction is 7.08 ＊ 10 -6 m/s. The saturated hydraulic conductivity in the vertical direction is 1. 147 ＊ 10 -5 m/s,and the measured one by the indoor test is 2.71 ＊ 10-5 m/s. The results are reliable.