新时期长江口航道建设深化研究方向的探讨

长江口航道的建设与管理面临着河势背景深刻变化的新情况和生态优先等新要求。为了进一步提高航道的综合通过能力,分析近几十年来长江口河势的主要变化,归纳长江口深水航道的治理(设计)思路。基于对长江口在盐、淡水交汇和潮汐环境中的黏性细颗粒泥沙运动物理过程和航道回淤机理的认识,包括盐度和含沙量的层化、紊动抑制、悬沙斜压效应以及纵向及横流输沙、悬沙近底高浓度层的类推移输运、浮泥的重力流输运以及非黏性沙的层移输运等,提出长江口航道建设、维护需要注意的问题和进一步的研究方向,以及开展河口开敞边界泥沙收支、生物对河床稳定性影响等研究的建议。分析结论和工作建议可作为深化长江口航道治理的参考。

Discussion on deepening research direction of waterway construction at the Yangtze River Estuary in the new era

The construction and management of the waterways at the Yangtze River Estuary are facing a new situation of profound changes in the river regime and new requirements such as ecological priority.To further improve the comprehensive carrying capacity of the waterways,we analyze the main changes in the river regime of the Yangtze River Estuary in recent decades and sum up the regulation(design)ideas for the deep waterways at the estuary.The physical process of viscous fine-grained sediment movement in fresh and salt water mixing and tidal environments and the mechanism of waterway siltation at the Yangtze River Estuary are sorted out,including the stratification of salinity and sediment concentration,turbulence suppression,baroclinic effect of suspended sediment,longitudinal and cross flow sediment transport,bedload like transport of suspended sediment near the bottom of the high concentration layer,gravity flow transport of floating mud,and laminar transport of non-cohesive sediment.On this basis,we point out some noteworthy problems in the construction and maintenance of the waterways at the Yangtze River Estuary and further research directions.We also put forward suggestions for studies of the sediment budget at the open boundary of the estuary and the influence of organisms on the stability of the riverbed.The conclusions and suggestions can serve as a reference for deepening waterway regulation at the Yangtze River Estuary.