花岗岩崩岗区不同土层的侵蚀水动力学特征

发布时间：2018-04-08 15:09

本文选题：崩岗　切入点：土壤剥蚀率　出处：《土壤学报》2017年03期

【摘要】：土壤剥蚀率是单位时间单位面积水流剥蚀土壤的质量,定量研究崩岗不同土层土壤剥蚀率对预测土壤剥蚀过程及建立崩岗侵蚀物理模型具有重要的理论和实践意义。针对湖北通城花岗岩崩岗区发育的表土层、红土层、砂土层、碎屑层,采用不同坡度(8.8%、17.6%、26.8%、36.4%、46.6%)和不同流量(0.2 Ls~(-1)、0.4 Ls~(-1)、0.6 Ls~(-1)、0.8 Ls~(-1)、1.0 Ls~(-1))相结合的室内放水冲刷试验,分析表土层、红土层、砂土层、碎屑层土体土壤剥蚀率与水动力学参数之间的关系,初步探讨花岗岩崩岗侵蚀的水动力学机制。结果表明:在一定坡度条件下,土壤剥蚀率随径流流量的增大而增大,且各土层土壤剥蚀率存在很大差异,碎屑层土壤剥蚀率最大,砂土层次之,表土层最小;在相同流量条件下,各土层土壤剥蚀率均随冲刷时间的延长逐渐降低并趋于稳定;径流剪切力、水流功率对崩岗各土层土壤剥蚀率的影响均可采用线性方程很好地描述(R~20.926),相比用单位水流功率拟合的多项式方程的相关性(R0.830)要高,径流剪切力和水流功率均可作为描述崩岗各土层土壤侵蚀的水动力学参数。表土层、红土层、砂土层、碎屑层的临界径流剪切力依次减小,分别为0.28Pa、0.13Pa、0.10Pa、0.07Pa,各土层土壤细沟可蚀性参数差异明显,碎屑层的最大,砂土层次之,表土层最小。因此,在崩岗垂直结构上,随着土层深度的增加,土体抵抗径流剥蚀的能力逐渐减弱。
[Abstract]:Soil denudation rate is the quality of water erosion soil per unit area of time. The quantitative study of soil erosion rate in different soil layers is of great theoretical and practical significance in predicting soil denudation process and establishing physical models of collapse erosion.The relationship between soil denudation rate and hydrodynamic parameters of clastic soil is discussed, and the hydrodynamic mechanism of granite collapse erosion is discussed.The results show that the soil erosion rate increases with the increase of runoff flow under certain slope condition, and there are great differences in soil erosion rate among different soil layers, the soil erosion rate of clastic layer is the largest, the sand layer is the smallest, and the top soil layer is the smallest.Under the same flow rate, the erosion rate of each soil layer decreases gradually with the extension of scouring time and tends to be stable.The effect of water power on soil erosion rate in various soil layers can be described by linear equation, which is higher than that of polynomial equation fitted by unit water power.Runoff shear stress and flow power can be used as hydrodynamic parameters to describe soil erosion in various soil layers.The critical runoff shear stress of the top layer, red soil layer, sand layer and clastic layer decreases in turn, which is 0.28 Pa0.13 Pa0.10 Pa0.07Pa. the erodibility parameters of each soil layer are obviously different, the maximum of the clastic layer, the minimum of the sand layer, and the minimum of the top layer.Therefore, with the increase of soil depth, the ability of soil to resist runoff erosion decreases gradually in the vertical structure of caving.
【作者单位】：华中农业大学资源与环境学院;农业部长江中下游耕地保育重点实验室;
【基金】：国家自然科学基金项目(41571258)资助~~
【分类号】：S157.1

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