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模拟降雨条件下红壤坡面侵蚀产沙水动力学特征
林庆明1,2, 丁文峰1,2, 张长伟1,2, 徐金鑫1,2, 方程3, 张平仓1,2
1.长江水利委员会长江科学院, 湖北 武汉 430010;2.水利部山洪地质灾害防治工程技术研究中心, 湖北 武汉 430010;3.河海大学, 江苏 南京 210093
摘要:
[目的]对红壤坡面侵蚀过程中的产流、产沙以及坡面径流水动力学参数进行试验研究,为揭示红壤坡面侵蚀产沙机理提供科学依据。[方法]以我国南方侵蚀性红壤为研究对象,采用人工模拟降雨法,通过不同坡度(6°,10°和15°),不同雨强(120,180和240 mm/h)条件下的模拟试验分析红壤坡面产流产沙过程及径流水动力学特征。[结果]在坡度一致时,坡面累积径流量和累积产沙量均随雨强的增大而增大,径流率表现为初期的波动增长,随降雨进行逐渐达到稳定状态,且径流率随坡度增大而增大;坡面产沙过程受坡度和雨强的双重影响;侵蚀产沙率呈降雨初期急剧上升,随后迅速下降并趋于平稳的趋势。试验坡面的径流水动力学特征表明,阻力系数f与雷诺数Re无明显的相关关系,但与弗洛德数Fr存在显著的指数关系。[结论]径流水动力学参数与侵蚀产沙量之间存在明显相关关系,相比较而言,径流雷诺数Re与坡面侵蚀产沙量间的关系最密切。
关键词:  模拟降雨  红壤  产流产沙  水动力学参数
DOI:10.13961/j.cnki.stbctb.2019.02.003
分类号:S157.1
基金项目:国家自然科学基金项目“基于土壤团聚体分形维和径流能耗分析的土壤可蚀性定量表征”(41271303);重大自然灾害监测预警与防范重点专项(2017YFC1502506)
Hydrodynamic Characteristics of Runoff in Red Slope Erosion Process Under Simulated Rainfall Experiments
Lin Qingming1,2, Ding Wenfeng1,2, Zhang Changwei1,2, Xu Jinxin1,2, Fang Cheng3, Zhang Pingcang1,2
1.Changjiang River Scientific Research Institute, Changjiang Water Resources Commission, Wuhan, Hubei 431000, China;2.Research Center on Mountain Torrents and Geologic Disaster Prevention, Ministry of Water Resources, Wuhan, Hubei 431000, China;3.Hohai University, Nanjing, Jiangsu 210093, China
Abstract:
[Objective] The experimental studied runoff yield, sediment yield and runoff hydrodynamic parameters during erosion process of red soil slope in order to provide the basis for revealing the mechanism of slope erosion and sediment yield on red soil slope.[Methods] Red soil was used, a total of 18 rainfall simulation experiments were conducted in a 8.0 m long drainable flume, with treatments including three levels of typical slope gradients (6°, 10°,15°) and three rainfall intensities (120, 180, 240 mm/h). The processes of runoff generation, sediment yielding, and runoff hydrodynamic characteristics variation were analyzed.[Results] The accumulative runoff and sediment load significantly increased with the increasing of rainfall intensity under the same slope gradient. The runoff rate variation showed a steady state after an initial increased fluctuation. The sediment yield rate increased with the increases of both rainfall intensity and slope gradient. The sediment generation process showed a variation that increased rapidly at the beginning and decreased quickly with the experiment time passed. There was a good exponent relationship between Froude numbers and Reynolds numbers, while flow Darcy-Weisbach friction coefficients and Reynolds numbers had no obvious correlation.[Conclusion] There is a significant correlation between runoff hydrodynamic parameters and erosion sediment yield. By comparison, Reynolds number of runoff is the most closely related to slope erosion sediment yield.
Key words:  simulated rainfall  red soil  runoff and sediment yielding  hydrodynamic parameters