| 引用本文: | 段凤仪,朱成立,王策,等.灌溉优先流对裂隙分布密度、灌水强度及土壤湿度的响应机理[J].灌溉排水学报,0,():-. |
| DUAN Fengyi,ZHU Chengli,WANG Ce,et al.灌溉优先流对裂隙分布密度、灌水强度及土壤湿度的响应机理[J].灌溉排水学报,0,():-. |
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| 摘要: |
| 【目的】为研究土壤初始含水率（土壤湿度）、裂隙分布密度及灌水强度对裂隙优先流强度的影响机理。【方法】本文构建了基于水量平衡原理的优先流双域渗透模型，并通过染色示踪试验进行物理模拟及模型验证，基于模型数值模拟了裂隙分布密度、初始含水率和灌水强度三维因素旋转组合下的优先流特征。【结果】试验区的浅小型裂隙（裂隙平均宽度0.2 cm≤wc≤1.0 cm，平均深度0.5 cm≤d≤10 cm）与优先流的发育无直接联系，宽深型裂隙（裂隙平均宽度wc≥2 cm，平均深度d≥50 cm）是产生裂隙优先流的主要原因；宽深型裂隙分布密度越大，基质流深度、染色面积率以及灌水均匀度增加；模型对裂隙优先流的模拟效果较好（R2=0.951，P＜0.01）；模拟结果显示，裂隙深度很大程度上决定了优先流的最大入渗深度；接近土壤饱和导水率的灌水强度无法触发优先流，随着灌水强度增加，优先流程度和最大入渗深度增加，基质流深度和灌水均匀度降低；随着土壤初始含水率和裂隙分布密度增大，基质流深度和灌水均匀度增加，优先流程度降低。【结论】对于缩胀性较强、有机质含量丰富的农田土壤，降低灌水强度、提高土壤初始含水率及裂隙分布密度能有效抑制裂隙优先流并提高灌水质量。 |
| 关键词: 裂隙优先流;双域渗透模型;裂隙分布密度;土壤初始含水率;灌水强度 |
| DOI： |
| 分类号:S152.7 |
| 基金项目:国家自然科学基金青年项目,江苏省自然科学基金青年基金项目,江西省水利科学院开放研究基金,国家科技奖后备培育项目,江西省重点研发计划项目 |
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| Mechanisms of Fracture Distribution Density, Irrigation Intensity and Antecedent Water Content on Crack Preferential Flow |
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DUAN Fengyi1, ZHU Chengli1, WANG Ce1, CHEN Yu2, MA Liang1
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1.Nanjing Hohai University;2.Jiangsu Rural Water Conservancy Science and Technology Development Center
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| Abstract: |
| 【Objective】To study the mechanism of the effect of initial soil moisture content, fracture distribution density and irrigation intensity on crack preferential flow intensity.【Method】In this paper, a A dual-permeability model for crack preferential flow based on the principle of water volume balance was constructed, and a dye tracing test was carried out for model validation. Furthermore, the above model was used to simulated the crack preferential flow under the rotating combination of fracture distribution density, antecedent water content and irrigation intensity.【Result】The shallow small cracks (average width between0.2 ~ 1.0 cm, average depth between 0.5 ~10 cm) in the test area were not directly related to the development of preferential flow, and the wide and deep cracks (average width above 2 cm, average depth above 50 cm) were the main cause of crack preferential flow; the greater the distribution density of cracks, the greater the matrix flow depth, staining area rate, and irrigation uniformity. The model was remarkably valid in predicting the crack preferential flow (R2 = 0.951, P < 0.01). The simulation results showed that the crack depth largely determined the maximum infiltration depth of preferential flow; Irrigation intensity close to soil saturated hydraulic conductivity could not trigger preferential flow and as the irrigation intensity increased the matrix flow depth and irrigation uniformity decreased, and the degree of preferential flow and maximum infiltration depth are significantly higher. As the antecedent water content of the soil and the density of the fissure distribution increased, the depth of substrate flow and the uniformity of irrigation increased and the degree of preferential flow decreased.【Conclusion】For the field soil with strong shrinkage and rich organic matter content, minimizing irrigation intensity, increasing antecedent soil water content and crack distribution density can effectively suppress crack preferential flow and improve irrigation quality. |
| Key words: crack preferential flow; dual-permeability models; fracture distribution density; antecedent water content; irrigation intensity |
