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Critical Conditions for Rill Initiation

机译:Rill启动的关键条件

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摘要

Quantifying critical conditions of rill formation can be useful for a better understanding of soil erosion processes. Current studies lack a consensus and related rationale on how to describe these conditions. This study was based on the concepts that (1) the shear stress available for erosion at any given point is a function of the runoff rate, the slope steepness, and hydraulic characteristics of the surface; (2) rill incision begins when overland flow shear stress exceeds soil critical shear stress; and (3) the distance from the top of the slope to the point where rills form can be measured and analyzed as length to rill initiation and decreases with increase in slope and rainfall intensity. These concepts were tested with a representative silty-clay soil from the Loess Plateau in northwestern China on a large sloping indoor plot (8 � 3 m), with five different slopes using simulated rainfall at three rainfall intensities. Values of several hydraulic parameters at rill initiation were determined from the experimental data. The results showed relationships among slope steepness, rainfall intensity, and location of rill initiation. It was found that slope was relatively more important than rainfall intensity in determining the location of rill initiation. Soil critical shear stress determined in this study ranged from 1.33 to 2.63 Pa, with an average of 1.94 Pa. Soil critical shear stress was inversely related to slope and was not influenced by rainfall intensity. The results of this study were comparable with those of previous investigators.
机译:量化小溪形成的关键条件可能有助于更好地了解土壤侵蚀过程。当前的研究缺乏关于如何描述这些情况的共识和相关的理论基础。这项研究基于以下概念:(1)在任何给定点可用于侵蚀的剪切应力是径流速率,坡度和表面水力特性的函数; (2)陆流切应力超过土壤临界切应力时开始开凿。 (3)可以测量和分析从斜坡顶部到小溪形成点的距离,并将其作为开始小溪的长度,并随着坡度和降雨强度的增加而减小。这些概念在中国西北黄土高原的一个典型的粉质粘土土壤上进行了测试,该土壤是在一个较大的倾斜室内地块(8×3 m)上,使用三个降雨强度下的模拟降雨在五个不同的坡度上进行了测试。从实验数据确定了在钻探开始时几个水力参数的值。结果表明,坡度,降雨强度和小溪起始位置之间存在关系。人们发现,在确定小溪发源地的位置上,坡度比降雨强度更为重要。本研究确定的土壤临界切应力范围为1.33至2.63 Pa,平均为1.94 Pa。土壤临界切应力与坡度成反比,不受降雨强度的影响。这项研究的结果与以前的研究者相当。

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  • 来源
    《Transactions of the ASABE》 |2008年第1期|p.107-114|共8页
  • 作者单位

    The authors are Chunmei Yao, Research Assistant, College of Hydraulic and Civil Engineering, China Agricultural University, Beijing, China, and Department of Biological Systems Engineering Department, Washington State University. Pullman, Washington;

    Tingwu Lei, ASABE Member Engineer, Professor, College of Hydraulic and Civil Engineering, China Agricultural University, Beijing, China;

    William J. Elliot, ASABE Member Engineer, Professor and Project Leader, Soil and Water Engineering, USDA Forest Service, Rocky Mountain Research Station. Moscow, Idaho;

    Donald K. McCool, ASABE Fellow, Research Leader, USDA-ARS Pacific West Area, Washington State University, Pullman, Washington;

    Jun Zhao, Senior Engineer, State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, China;

    and Shulin Chen, ASABE Member Engineer, Professor, Department of Biological Systems Engineering, Washington State University, Pullman, Washington. Corresponding author: Shulin Chen, Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120;

    phone: 1-509-335-3743;

    fax: 1-509-335-2722;

    e-mail: chens@wsu.edu.;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Critical condition, Critical shear, Erosion, Hillslope, Rill initiation;

    机译:临界条件;临界剪切;侵蚀;坡度;Rill引发;

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