土柱尺寸对扰动黏壤土饱和导水率的影响

Effects of column size on soil saturated hydraulic conductivity of clay loam

土壤饱和导水率Ks是最基本的水力参数之一,而已知实验室内其值的确定受土柱尺寸的影响.以关中的塿土为研究对象,在室内,采用定水头法,研究5～30 cm内6个不同土柱尺寸对扰动黏壤土Ka测定的影响.结果表明：随着时间的延伸,Ks逐渐减小,其值最初降幅较大,其后趋于稳定,且在5 ～ 30 cm土柱直径范围内,Ks随着土柱直径的变大,扰动黏壤土的Ks递增,二者线性相关,y=0.000 4x＋0.003 7（R2=0.965 1）.研究结果可为测定Ks合理测定时间段及合理尺寸的选择提供参考.

Soil saturated hydraulic conductivity （Ks） is one of the most important hydraulic parameters,and its determination in the laboratory has been shown to be influenced largely by column size.This study estimates measurements of Ks in the lab using six different column sizes：5,10,15,18,23 and 29.5 cm.Constant water head method was used,and disturbed Lou soil,a typical clay loam soil in Guanzhong region,was selected.Results showed that Ks decreased over time,and the range of descending changed greater at the initial stage than later.At the column size range of 5-30 cm,Ks decreased with increasing column size.A linear regression analysis of two data sets of Ks and column size showed that the Ks data were linearly correlated with the size data following y =0.000 4x ＋ 0.003 7 （R2 =0.965 1）.This study may serve as reference to choose reasonable time and size in measuring the Ks of disturbed soils.