Scholarlink

<p>This study investigates the incipient motion characteristics of uniform and non-uniform sediments in the source region of the Yangtze River through flume experiments, focusing on the effects of particle shape, grain size distribution, and hydraulic conditions on critical Shields stress. Adopting the sediment transport intensity criterion (I = 10<sup>−4</sup>s<sup>−1</sup>) proposed by Shvidchenko and Pender (Water Resour Res 36:619–628, 2000. <a href="https://doi.org/10.1029/1999wr900312">https://doi.org/10.1029/1999wr900312</a>), the critical shear stress was calculated using four methods: vertical average velocity, logarithmic velocity profile, resistance balance, and near-bed three-point velocity. Results indicate that irregularly shaped Yangtze source sediments (sphericity coefficient 0.671 vs. 0.893 for rounded sands) exhibit higher critical Shields stress than conventional sands. Fine grains are harder to entrain in non-uniform sediments due to hiding effects, while coarse grains are mobilized more readily due to protrusion. A revised Shields diagram based on experimental data reveals systematic overestimation by traditional methods at high Reynolds numbers (Re&gt;500), suggesting the logarithmic velocity profile method for improved accuracy. These findings provide theoretical support for evaluating riverbed stability and optimizing sediment transport models in the Yangtze River source area.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Experimental study on sediment incipient motion characteristics in the Yangtze river source region

  • 期刊论文

  • 发表日期：

    2025年10月7日

查看全文
  • Zhijing Li,
  • Xiaoxue Wang,
  • Wenqi Li,
  • Yujiao Liu,
  • Junxiao Ma,
  • Zhixian Cao

摘要

This study investigates the incipient motion characteristics of uniform and non-uniform sediments in the source region of the Yangtze River through flume experiments, focusing on the effects of particle shape, grain size distribution, and hydraulic conditions on critical Shields stress. Adopting the sediment transport intensity criterion (I = 10−4s−1) proposed by Shvidchenko and Pender (Water Resour Res 36:619–628, 2000. https://doi.org/10.1029/1999wr900312), the critical shear stress was calculated using four methods: vertical average velocity, logarithmic velocity profile, resistance balance, and near-bed three-point velocity. Results indicate that irregularly shaped Yangtze source sediments (sphericity coefficient 0.671 vs. 0.893 for rounded sands) exhibit higher critical Shields stress than conventional sands. Fine grains are harder to entrain in non-uniform sediments due to hiding effects, while coarse grains are mobilized more readily due to protrusion. A revised Shields diagram based on experimental data reveals systematic overestimation by traditional methods at high Reynolds numbers (Re>500), suggesting the logarithmic velocity profile method for improved accuracy. These findings provide theoretical support for evaluating riverbed stability and optimizing sediment transport models in the Yangtze River source area.