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| DOI：10.13522/j.cnki.ggps.2019132 |
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| Three-dimensional Model and Verification of Soil Wetting Front Migration in Negative Head Environment |
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ZHU Jun , LI Ting , XIE Tian , ZHANG Aiming
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China Institute for Radiation Protection Key Laboratory of Nuclear Environmental Simulation and Evaluation Technology, Taiyuan 030006, China
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| Abstract: |
| 【Objective】This study aimed to control soil water content more effectively and guide water-saving irrigation.【Method】The sand and loam in Yuci area of Shanxi Province were selected to establish soil wetting front migration experiments under three kinds of negative head height(0 m，-0.5 m，-1.0 m). The negative head soil moisture wetting front migration test and Hydrus-3D soil moisture migration numerical model were used to research the law of soil moisture wetting front migration and the validity of the model.【Result】The cumulative infiltration increases with the increase of time, and also can be expressed by power function. With the increase of time, the wetting front gradually expands to horizontal and vertical directions, and not only the curve presents a 1/4 elliptic shape, but also the maximum wetting distance with the square root of time can be expressed by linear relation. The infiltration velocity of wetting front decreases with the increase of negative head height and can be expressed by power function too. The measured wetting front envelope area at negative head of -0.5 m and -1.0 m was used as model validation data. The deviation of wetting front envelope area between numerical calculation and measured, is 0.51%～7.21% for sandy soiland 0.22%～16.03% for loam.【Conclusion】The three-dimensional model can be used to describe the migration characteristics of soil wetting front in negative head environment, and to predict the movement and distribution of moisture content under different conditions. |
| Key words: negative head; cumulative infiltration; water front; infiltration velocity; Hydrus-3D |
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