| 河床粗化过程中推移质输移特征试验研究 |
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| 引用本文： | 徐元,朱德军,孟震,李丹勋.河床粗化过程中推移质输移特征试验研究[J].水科学进展,2018,29(3):339-347. |
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| 作者姓名： | 徐元 朱德军 孟震 李丹勋 |
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| 作者单位： | 清华大学水沙科学与水利水电工程国家重点实验室, 北京 100084 |
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| 基金项目： | 国家自然科学基金资助项目（51509136；51379101） |
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| 摘 要： | 为了研究河床粗化破坏与形成过程中推移质的输移特征，基于一套新型的接沙系统，在上游无来沙条件下，进行了3组不同床沙级配的水槽试验，研究了递增梯级流量作用下河床粗化破坏与形成的过程，采集到一套高精度（0.1 g）、高频率（1 Hz）的实时推移质输沙率及分时段输沙级配数据，分析了累积输沙量、输沙率及输沙级配的变化特征。结果表明，粗化过程中累积输沙量随时间基本呈幂函数规律增长，且"粗化破坏再形成"的累积输沙量曲线出现明显转折点；推移质输沙率表现出明显的非恒定性，其粗化形成阶段的耗时要远大于粗化破坏阶段的时间，两者之比范围为3.5~20.5；推移质输沙级配中粗颗粒比例随时间变化趋势与输沙率相似，在输沙率达到峰值附近时，输沙级配与原始床沙级配相同。
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| 关 键 词： | 推移质 输沙率 级配 河床粗化 输移特征 |
| 收稿时间： | 2017-09-12 |
Experimental study on bed load transport in the armoring process |
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| XU Yuan,ZHU Dejun,MENG Zhen,LI Danxun.Experimental study on bed load transport in the armoring process[J].Advances in Water Science,2018,29(3):339-347. |
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| Authors: | XU Yuan ZHU Dejun MENG Zhen LI Danxun |
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| Affiliation: | State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China |
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| Abstract: | To study the characteristics of bed load transport during armor breakup and reformation, three groups of long-duration laboratory experiments were conducted without sediment supply. Each experiment group employed a stepwise increasing discharge. The bed materials used were composed of a fine fraction and a coarse fraction, with diameters of 1.22 mm and 3.74 mm, respectively. Accurate and high-resolution data of real-time bed load grain size and sediment transport rates were acquired from the experiments with the help of a newly designed sediment trap. Then, the evolution of the cumulative transported mass, bed-load transport rates and the grain size of the bed load were analyzed. The results show that the cumulative mass exhibits a power function relation with time and that there are turning points along the curves during armor breakup and reformation. The bed-load transport rates are highly unsteady, and the duration of the armor formation phase is 3.5 to 20.5 times longer than that of the breakup phase. The coarse fraction and transport rate of the bed load vary with time in a similar manner. When the transport rate peaks, the coarse fraction of the bed load is equal to the coarse fraction of the bed materials. |
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| Keywords: | bed load transport rate grain size riverbed armor transport features |
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