土壤渗透参数空间变异性的试验研究

Field Experimental Study of the Spatial Variability of the Unsaturated Soil

通过野外布点试验 ,应用Guelph渗透仪测得了各点的土壤饱和渗透系数Kfs 和土壤特性参数α。对试验结果分析表明 ,Kfs和α两参数具有较大的空间变异性 ,并服从对数正态分布。应用指数解析模型模拟了lnKfs和lnα两空间随机变量的半方差函数 ,拟合模型所得到的方差与实验结果的统计值基本接近 ,两参数的相关距离分别为 6m和 10m。

The saturated conductivity K\-\{fs\} and the soil characteristic parameter α in the Gardner model of the unsaturated soil conductivity are measured at about 91 points in the field by using Guelph permeameter. It is shown that there is a large variability of parameters K\-\{fs\} and α , and the two parameters both obey the log normal distribution. Analytical models are used for the simulation of the spatial distribution of K\-\{fs\} and α . The simulation result shows that the variance from the model is very close to the statistical value from the experimental data. The correlation scales are 6 m and 10 m for K\-\{fs\} and α , respectively. The determined spatial statistical structure and moments can be used for the determination of the macro_dispersivity and the macro_conductivity of the unsaturated soil, which are very difficult to be measured from the filed experiments.