Estimation of the Critical Infiltration Rate for Air Compression During Infiltration
Estimation of the Critical Infiltration Rate for Air Compression During Infiltration
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DOI：
10.1029/2019wr026410
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发表时间：
2020-03
影响因子：
5.4
通讯作者：
Yunbo Wei;Kouping Chen;Jichun Wu
中科院分区：
文献类型：
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作者：
Yunbo Wei;Kouping Chen;Jichun Wu
在强降雨或洪水灌溉期间，空气可能被压缩到非饱和区湿润锋面以下，从而减少入渗，从而导致过量径流和土壤侵蚀。然而，估计导致空气压缩的临界渗透率(Icrit)仍然很困难。在这项研究中，对空气压缩的临界渗透率进行了实验和分析。在渗透实验中，当渗透速率超过工作沙的某一临界速率时，观察到显著的空气压缩。这一测得的临界速率随着沙粒尺寸的增大而增大。然后提出了一种创新的分析方法，利用砂岩的参数估计Icrit的价值。当考虑空气的阻抗时，估算的Icrit与实验中测量的Icrit吻合较好。基于解析法，提出了预测多孔介质临界温度的方程。根据该方程，Icrit的值由多孔介质的渗透率和孔径分布决定。结果表明，Icrit随多孔介质渗透率的增大而增大，随介质孔径变得更加均匀而增大。
During intense rainfall or flood irrigation, air may be compressed below the wetting front in the unsaturated zone, which reduces infiltration and thereby leads to excessive runoff and soil erosion. However, estimation of the critical infiltration rate (Icrit) that leads to air compression remains difficult. In this study, the critical infiltration rate for air compression was investigated experimentally and analytically. During infiltration experiments, significant air compression was observed as the infiltration rate excessed some critical rate for the working sands. And this measured critical rate increased as particle size of the sand increased. An innovative analytical approach was then proposed to estimate the values of Icrit using the parameters of the sands. When taking the impedance of air into consideration, the estimated Icrit matched well with the measured Icrit in the experiments. Based on the analytical approach, an equation was proposed to predict Icrit for a porous medium. According to the equation, the value of Icrit was determined by the permeability and pore size distribution of the porous medium. It was found that Icrit increased with the permeability of the porous medium, and also increased as the pore size of the medium became more uniform.