黄河下游高含沙水流输沙的可能性与制约因素

Possibility and Restrictive Factors of Sediment Transport by Hyper Concentration Flow in the Lower Yellow River

鉴于黄河历史上曾出现过主槽冲刷状态下的高含沙洪水,考虑到高含沙洪水的强大输沙能力,围绕黄河下游的高含沙洪水泥沙输送能力开展了研究,并对一般挟沙水流和高含沙水流的临界含沙量进行了定量计算。结果表明:天然条件下可实现使河道处于冲刷状态的高含沙洪水,其水沙条件具有一定的特殊性,特别是经过河道沿程天然筛选后的级配与含沙量需满足一定的条件;长距离输沙时,持续的高含沙历时也是远距离传播的必要条件之一。

In view of the history of the Yellow River , there have been hyper concentration floods under the condition of channel scouring. Considering the powerful sediment transport capacity of hyper concentration floods , this paper studied the possibility of adopting hyper concentration floods mode to transport plenty of sediment in the lower reaches of the Yellow River , and made a quantitative analysis of the critical conditions of hyper concentration flow to achieve the equilibrium of scouring and silting and even the state of channel scouring. Quantitative calculation was carried out at the Huayuankou section , and the variation of relative sediment transport capacity was taken as the main physical quantity to carry out the analysis and comparison under different water and sand conditions. The results show that the hyper concentration floods under natural conditions in the balance of scouring and silting have certain particularities , especially the relationship between gradation and sediment concentration might satisfy certain conditions with exchanging of suspended sediment and bed sediment along the river. In addition , the continuous duration of hyper concentration is one of the necessary conditions for long-distance sediment transport.