包气带垂向渗透系数的原位试验研究

Experiment of original position of vertical hydraulic conductivity at unsaturated zone

野外试验测定包气带渗透系数对于研究非饱和带水分运移过程、植物根系吸水特征及产汇流规律具有重要意义。本文采用Inverse Auger法在毛乌素沙地开展了原位包气带垂向渗透系数测定实验。通过实验数据分析表明:①为获得较可靠的垂向渗透系数,野外实验时,需要重复注水过程,使包气带应尽可能湿润,消除水平吸渗对垂向入渗的影响;②采用Porchet推导的计算公式计算包气带垂向渗透系数时,应对获取的数据进行统计分析,放弃不符合实验物理背景的数据。在上述分析基础上,计算得到实验介质平均垂向渗透系数为2.23 cm/h。上述原位实验数据的分析方法和实验结果对相关实验研究具有一定的借鉴意义。

The vertical hydraulic conductivity of unsaturated zone plays a very important role in the research of dynamic transport of water, root water uptake character and rule of surface water flow. This paper used inverse auger method to carry out the situ experiment of hydraulic conductivity of unsaturated zone in Maowusuo Desert. Data analyses indicate that：①in order to get vertical seepage conductivity, water should be supplied again so as to make unsaturated zone maintain moisture and diminish the effect of horizontal flow ; ② when calculating vertical seepage coefficient by means of Porchet formula, statistics analysis tools can be used to discard err data of not in accordance with physics background. On the context of data analysis as mentioned, the vertical hydraulic conductivity of the experimental soil is 2.23 cm/h. The analysis methods and the experimental results have certain significance for related experiment.