长江下游口岸直水道鳗鱼沙浅滩段河床演变与航道整治思路

鳗鱼沙浅滩位于长江下游口岸直水道下段,属典型的顺直宽浅水下分汊型沙质浅滩。演变分析表明该段的航道条件与鳗鱼沙心滩形态密切相关,当鳗鱼沙高大完整时,航道条件就好;反之,航道条件就差。本段顺直宽浅河床形态决定了该段滩槽不稳定的现象将长期存在,特别是上游来沙量的减少,将导致心滩易冲难淤,碍航问题将更为严峻。在总结河段浅滩碍航特性的基础上提出了保持现有一滩两槽格局、加高加大心滩、调整滩槽水流分布、增加浅区的冲刷能力的整治思路,以期解决口岸直水道鳗鱼沙浅滩段的碍航问题。

River bed evolution and waterway regulation thought of Manyusha shoal in Kou'an straight reach of the Yangtze River

Manyusha shoal,located in the Kou’an straight reach,is a main navigation obstacle in the lower reaches of the Yangtze River.Based on the evolution character in the recent period,it shows that the navigation obstacle character is closely related with the scale of Manyusha shoal.Higher and more integral the shoal is,better the navigation condition is.It is concluded that Manyusha shoal and the left and right deep pools produce much scouring-silting change,which is the main cause of the formation of the shoa1,Especially,the reduction of sediment coming from upstream will result in that the shoal is easy to be eroded,while hard to be deposit.So the navigation condition will be severe.Based on an analysis of the navigation obstructing features of the shoal section,this paper proposes the regulation idea which is to maintain the existing pattern of one pool of two slots,to increase and heighten the central bar and adjust the flow distribution of riffle and pool so as to increase the scouring capability of shallow areas and solve the problem of navigation obstruction at the Manyusha shoal of Kou’an straight reach.