水分再分布过程中指流特性及影响因素的实验研究
网络出版日期: 2010-02-25
基金资助
国家自然科学基金项目(50979090；90610030）；国家重大科技水专项（2009ZX07212-002-005)
Experimental Research on Characteristics and Affecting Factors of Finger Flow during Redistribution in Sandy Soil
Online published: 2010-02-25
水分在土壤中的运移过程可分为土体表面存在水分供给的入渗过程和水分供给结束后水分在土体中的再分布过程两个阶段。指流作为一种优先流，区别于大孔隙流和漏斗流。国外已有研究指出，指流可以在充分供水结束后的土壤水分再分布过程中出现。然而，目前国内对指流的研究极少，对其认识和理解也相当缺乏。由此，本文采用石英砂介质对其进行了实验验证，分析了水分再分布过程中指流的特性；同时探讨了前期供水量、实验土箱尺寸、溶液浓度等因素对其发育的影响。研究结果表明，水分再分布过程中，均匀砂质土体中易于出现指流；前期供水量的多少对随后水分再分布过程中指流发育的最终形态影响不大，但能够对指流发育进程产生明显的影响；实验土箱较小时，可使原来指流发生比较明显的土体系统呈现出稳定形态；增大单一溶液的浓度对指流发育有着明显的促进作用，但其指流现象较采用自来水的处理为弱。
关键词： 指流；影响因素；水分再分布过程；实验研究
李贺丽1,2,3|李怀恩2|胥彦玲4 . 水分再分布过程中指流特性及影响因素的实验研究[J]. 地理科学进展, 2010 , 29(2) : 173 -178 . DOI: 10.11820/dlkxjz.2010.02.007
The process of water transferring through soil zone can be divided into two phases: the foregoing infiltration and the following redistribution. Finger flow as a form of the preferential flow of water, differs from macro-pore flow and funnel flow. It has been validated that finger flow can occur during the redistribution following the infiltration of soil water. However, domestic studies on finger flow are very few at present, and cognition about it is very scarce either. Hereby, in this paper, the experiments were designed to discuss the characteristics and the effects of different factors on the development of finger flow during redistribution with a sandy soil. The affecting factors included the quantity of the water supplied in prior process of infiltration, the size of the experimental box, the fluid characteristics and so on. The major results are as follows: finger flow can develop easily during water redistribution process with prior sufficient water supply; the quantity of water increased in prior process of infiltration has little influence on the final form of finger flow developed whereas quickens the speed of the finger flow development; the smaller experiment box can restrain the development of finger flow；the finger flow develops faster with a clearer form during the water redistribution process when the concentration of simplex solution is increased, but when compared with the experiment in which tap water is used, the experimental result is reversed.
Key words： affecting factors; experimental research; finger flow; redistribution
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