不同粒径红壤团聚体坡面溅蚀特征

发布时间：2018-08-14 13:20

【摘要】：为揭示不同粒径团聚体坡面溅蚀规律,以第四纪粘土发育红壤为研究对象,通过室内人工模拟降雨试验(雨强75mm/h,历时45min)研究0.25,0.25~0.5,0.5~1,1~2,2~5mm粒径团聚体溅蚀规律,系统分析了降雨条件下各粒径团聚体破碎、溅蚀率变化、溅蚀搬运量以及溅蚀搬运后的空间分布特征。结果表明:(1)降雨条件下团聚体粒径越大越容易破碎,除2~5mm团聚体破碎量高达96.06%外,2mm团聚体破碎量均小于50.00%。(2)0.25mm团聚体溅蚀率具有陡涨陡落特点,表土结皮发育迅速;0.25~0.5mm团聚体溅蚀率陡涨缓落,表土泥浆化过程明显;0.5~5mm团聚体溅蚀率则能保持较长时间增长,随后降低。(3)不同粒径团聚体溅蚀总量、上下坡溅蚀量与净搬运量变化趋势一致,一次降雨过程中,溅蚀搬运量峰值出现在粒径0.25~0.5mm范围内,而后随着粒径的增大逐渐降低。(4)团聚体粒径越小,溅蚀搬运后的平均重量距离越大,各粒径团聚体溅蚀量基本全部分布在半径60cm范围内。研究结果能为降雨侵蚀防治及侵蚀过程模型提供理论参考。
[Abstract]:In order to reveal the law of splash erosion on slope of aggregates with different particle sizes, the splash erosion rule of 0.25 ~ 0.25 ~ 0.25 ~ 0.55 ~ 0.51 ~ 0.51 ~ 0.51 ~ (1) ~ (?) ~ (2) ~ (2) ~ (2) ~ (2) ~ (5) mm aggregate was studied by simulated rainfall test (75 mm / h, 45min) in the Quaternary clay developed red soil. The fragmentation of aggregates, the variation of splash rate, the amount of splash transport and the spatial distribution of the particles were systematically analyzed under the condition of rainfall. The results are as follows: (1) the larger the aggregate size is, the easier it is to break down under rainfall conditions, except that the fragmentation amount of 2~5mm agglomerates is up to 96.06% and the fragmentation amount of 2 mm aggregates is less than 50.000.The splash erosion rate of 0.25mm aggregates has the characteristics of steep rise and steep fall. The spatter erosion rate of 0.25 ~ 0.5mm agglomerates increases and drops slowly, while the spatter erosion rate of 0.5mm agglomerates increases for a long time and then decreases. (3) the total amount of spatter erosion of aggregates with different particle sizes increases. During a single rainfall, the peak value of splash transport appears in the range of particle size 0.25~0.5mm, and then decreases gradually with the increase of particle size. (4) the smaller the particle size, the smaller the particle size. The larger the average weight distance is, the larger the splashing amount of agglomerates is in the radius 60cm range. The results can provide theoretical reference for rainfall erosion control and erosion process model.
【作者单位】：华中农业大学水土保持研究中心;沈阳农业大学水利学院;
【基金】：国家自然科学基金项目(41301285;40901132)
【分类号】：S157.1

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