上荆江分汊性微弯河段河床演变原因探讨

Analysis of river channel process of bifurcated and slightly curving channel in Upper Jingjiang River

受河岸组成、人工护岸工程的控制,上荆江河道平面外形基本稳定,但分汊性微弯河段河势调整较为剧烈,影响航道条件。本文基于不同河段的河床平面形态、水沙输移特性、河床演变规律的对比分析,认识到水沙输移特性既与河床平面形态密切相关,又直接影响河床演变对水沙条件的响应模式;基于此观点,对三峡工程蓄水以来上荆江分汊性微弯河段的演变特性进行了分析,进而预测分析了三峡正常蓄水后的河床演变趋势,可供航道治理参考。

Under the control of natural nodes and bank protection works,the plan-form of the Upper Jingjiang River is basically stable,but the local river regime in the bifurcated and slightly curving channel adjusts largely,impacting on channel navigation conditions.Aiming at this kind of river reaches,this paper comparatively analyzes their riverbed plan-forms,channel evolution laws and water and sediment transport characteristics.The water and sediment transport characteristics are closely related to the riverbed plan-form,and directly impact on the model of riverbed evolution in response to water and sediment conditions.Based on this view,the riverbed evolution of the bifurcated and slightly curving channels in the Upper Jingjiang River since the commissioning of the Three Gorges Project is analyzed,moreover,their evolution trend after the Three Gorges Project normal impoundment is forecasted to guide channel navigation regulation.