长江上游斗笠子滩近期航道条件变化及维护对策分析

Recent waterway condition changes and maintenance countermeasures of Doulizi Beach in upper reaches of the Yangtze River

斗笠子滩为长江上游枯水浅急险滩,经采取筑坝和疏浚的整治措施后,航道条件好转。采用实测资料分析滩段近年的水沙条件、滩槽格局及航道条件变化,并结合2019年以来的航道维护疏浚实施情况和效果提出相应的治理方案。结果表明,近年来向家坝蓄水后受清水下泄和人为采砂活动影响,左岸边滩冲退是造成江心庙角碛碛翅—碛尾段不断淤积展宽、航道维护困难的主要原因,且在目前的河势和水沙条件下,左岸边滩不具备自然恢复的条件,滩段枯水期淤积碍航将成为常态;汛后提前疏浚的维护方式和加抛整治建筑物的治理方案可减小低水位期疏浚施工与正常通航存在的安全风险。

The Doulizi Beach is a low-water and rapid shoal in the upper reaches of the Yangtze River.After the damming and dredging measures are taken,the waterway conditions are improved.This study uses the measured data to analyze the changes in water-sediment conditions,patterns of floodplains and main channels,and waterway conditions in recent years.It proposes a regulation scheme considering the implementation and effect of waterway maintenance and dredging since 2019.The results reveal that under the influence of clear water discharge after Xiangjiaba impoundment and artificial sand mining activities,the scouring and retreat of the left marginal bank is the main reason for the continuous siltation and widening of the moraine wing and tail section of the Miaojiaoqi moraine and difficult waterway maintenance.Under the current river regime and water-sediment conditions,the left marginal bank does not have the conditions for natural recovery,and the siltation and navigation obstruction of the Miaojiaoqi Beach in the dry season will become the norm.The maintenance mode of early dredging after the flood season and the regulation scheme of adding new regulation buildings can reduce the safety risks in dredging construction and normal navigation.