顺直过渡段卵石浅滩形成条件分析

Analysis of formation of gravel shoals at the straight transition region

长江上游河段分布众多卵石浅滩,大多数属于碍航浅滩,通过对卵石浅滩形成条件的分析,深入了解浅滩的碍航成因,为航道整治提供一定的理论基础。基于对卵石浅滩成因与演变的分析,从泥沙起动机理和卵石浅滩形成的基础出发,导出了顺直过渡段卵石浅滩形成可能性的比降和河道宽深比的范围区间。利用大量的野外实测资料和试验资料进行验证,结果表明卵石浅滩形成是在一定的比降或河宽范围内的,同时提出了相对应的上下限表达式。

There are lots of gravel shoals in upper course of the Yangtze River. Most of these gravel shoals hindered the passing of ships.The formation conditions and the navigation-obstructing characteristics of gravel shoals are discussed which provides more basic theories and information for regulation measurement.Based on the analysis of formation and evolution of gravel shoal, the research deduces the criterions of formation of gravel shoals through the mechanism of sediment incipient.The result shows that the gravel shoal can be formed in a certain range on both of channel slope and channel width.The formula verified by a large amount of field data and experimental data.