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在分析前人的不平衡输沙研究成果的基础上 ,针对非均匀沙河床 ,提出了床沙交换速率的新物理概念 ,计算研究了不同床沙交换速率时表层床沙的粗化过程及非均匀沙含沙量恢复饱和过程。研究表明 ,由于较细泥沙的冲刷率总大于较粗泥沙 ,因此在床面薄层内泥沙随冲刷迅速粗化 ,致使挟沙力降低 ,不平衡输沙距离较均匀沙情况大大延长。床沙交换速率愈慢 ,则冲刷距离愈长。
On the basis of analyzing the previous research results of unbalanced sediment transport, a new physical concept of bed-sand exchange rate was proposed for non-uniform Shahe bed, and the coarsening process of surface bed sand with different bed-sand exchange rates was studied. Sand uniform sand to restore the process of saturation. The results show that sedimentation rate of sediment in the bed is rapidly roughened with erosion because the erosion rate of fine sediment is always greater than that of coarse sediment, resulting in a decrease of sediment-carrying capacity and a much longer distance of unbalanced sediment transport than that of uniform sand . The slower the bed exchange rate, the longer the scour distance.