测定砂土水分特征曲线的一种简易方法

A simple method for measuring the moisture characteristic curves of sandy soils

土壤水分特征曲线反映了土壤含水率与吸力之间的关系,是研究土壤水分流动和溶质运移的基础数据。对于砂性土,提出一种测定水分特征曲线的简易试验方法,即对砂柱进行逐级排水,获得排水量与自由面(潜水面)高度的关系曲线,将其转化为水分特征曲线。采用这种砂柱试验测定了地大粗砂的土壤水分特征曲线,得到了良好的"S"型曲线,能够用Van Genuchten公式进行拟合。砂柱试验结果与压力膜仪法实测的和Arya-Paris模型间接推求的土壤水分特征曲线具有一致性。与现有测定方法相比,砂柱实验具有原理简单、准确度较高、成本低的优势。

The characteristic curves of soil moisture, which refer to the relationship between the water content and the matrix suction, are the basis for solving the problems of water flow and the solute movement in soils. A simple experimental method is developed to measure the curves for sandy soils. In this method, the water in the sand column is discharged gradually to obtain the relationship curve between the discharge of water and the height of free surface （water table）, which is then transformed into the characteristic curve of soil moisture. The characteristic curves of the CUGB coarse sand measured by the proposed method present the shape S which could be fitted using the Van Genuchten formula. The results are consistent with the characteristic curves obtained by using the pressure-membrane apparatus and the Arya-Paris model. Compared with the widely used existing methods, the proposed method which relies on the laboratory experiment of sand column is of the advantages such as the simple principle, the high accuracy and the low cost.