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洪水侵蚀沟床形成泥石流是泥石流的主要类型之一,研究其形成机理和形成的临界条件有助于泥石流治理和预警预报。借鉴河流动力学中推移质输沙理论,对已有洪水侵蚀沟床形成泥石流的水槽试验资料分析表明,洪水侵蚀沟床所形成泥石流的体积输沙浓度随沟床固体颗粒物质无量纲切应力的增大而增大,且呈幂函数关系。采用定量标准作为泥石流形成判别条件,则泥石流形成临界条件是体积输沙浓度计算公式的一个特例,此时床面颗粒无量纲切应力为0.655,远大于泥沙颗粒起动无量纲切应力。基于10组水槽试验资料和1组蒋家沟原型观测资料的适用性分析表明,建立的体积输沙浓度计算公式是合理的,能够反映泥石流形成和输移规律,可用于指导泥石流形成临界水力条件的计算。
Abstract：Debris flow due to channel-bed failure is one of main types of debris flow. Study on critical condition for initiation of debris flow is very important for prevention and early-warning of debris flows. Analysis based on bed load transport theory and debris flow experimental results shows that solid transportation concentration increases with the increase of dimensionless bed shear stress with a power function between solid transportation concentration and dimensionless bed shear stress. Quantitative standard is adopted to describe the initiation of debris flow. Quantitative standard is adopted to describe the initiation of debris flow in this paper,and the critical condition for initiation of debris flow due to channel-bed failure is a special case of the formula which is established to predict the solid transportation concentration. Results show that imitation of debris flow requires heightened dimensionless bed shear stress. Analysis of performance and applicability based on 10 sets of flume experiment data and 1 set of field data in Jiangjia Gully indicates that the model in this paper can be used to estimate the critical condition for initiation of debris flow.
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基本信息:
DOI：10.16239/j.cnki.0468-155x.2018.01.007
中图分类号:P642.23
引用信息:
[1]王涛,陈宁生,邓明枫,等.洪水侵蚀沟床形成泥石流的临界水力条件研究[J].泥沙研究,2018,43(01):38-43.DOI:10.16239/j.cnki.0468-155x.2018.01.007.
基金信息:
国家自然科学基金项目(51409243,41661134012)