维持黄河下游河槽排洪输沙能力方案分析

利用黄河下游水动力学泥沙冲淤数学模型,采用3个20年设计水沙系列对河段的冲淤及平滩流量的变化进行了计算与分析,结果表明:①各水沙系列的前10年,下游各河段均处于沿程冲刷状态,而后10年各河段则出现了淤积;②只有系列2能维持整个下游河道的平滩流量在4000 m3/s以上;③各系列前10年塑造河槽阶段的水沙过程均比较合理,基本实现了平滩流量稳定增大的目的,后10年河道平滩流量则出现了不同程度的减小;④应尽量控制小浪底出库含沙量不超过200 kg/m3且细泥沙比重在75%以上。

Analysis on Plan of Keeping the Capability of Sediment and Water Discharge of the Lower Yellow River Channel

It calculates and analyzes the variations of scouring and bankfull discharge by using mathematical model of hydrody-namics and sediment scouring of the lower Yellow River and using 3 twenty years sediment discharge series.The outcomes show that a) each section is in the state of scouring in the first 10 years of sediment discharge series and deposition happens in the second 10 years;b) only series 2 can keep the bankfull discharge greater than 4,000 m3/s in the whole lower river channel;c) the silt-discharge process for forming the channel in the first 10 years is rational,basically achieving the target of stable and increased bankfull discharge and the bankfull discharge is reduced to varying degrees in the second 10 years and;d) it should try to control the sediment concentration of outflow of the Xiaolangdi Reservoir less than 200 kg/m3 and the specific gravity of fine sands greater than 75%.