荆江典型碍航河段航道整治工程对三峡蓄水适应性分析

Adaptability of regulation projects in Jingjiang navigationobstructing sections to Three Gorges reservoir impounding

针对三峡蓄水过程中的荆江典型碍航河段,研究了航道整治工程对蓄水过程的适应性及工程效果。通过实测水沙、地形资料,分析了三峡蓄水后荆江河段河床冲淤规律及航道条件变化,以窑监河段为研究对象,采用二维水沙数学模型模拟了守护型工程和调整型工程对于汛后蓄水过程的适应性。结果表明:在三峡水库蓄水后"清水冲刷"的前提条件下,守护型工程对改善航道效果有着积极作用,但需满足一定条件,主要是浅水道处于较好的演变阶段,并且整治目标与现状条件差距不大;而对三峡水库汛后蓄水过程较为敏感的河段,彻底改善或提高航道条件,需采用一定的调整型整治工程。研究成果可供三峡工程坝下河段航道整治研究等参考。

This paper reports a study on the responses of waterway regulation projects to the Three Gorges reservoir impounding and the effects of a typical regulated navigation-obstructing section of the Jingjiang River during the impounding. Measured data of the river flow, sediment transport and topography were adopted in this study to analyze the trends of riverbed scour and deposition and the changes in waterway conditions in the regulated Yaojiang bend section after the impounding. We used a two-dimensional flow and sediment transport mathematical model to simulate this bend section and the actual effects of its guard projects and adjustable projects at an impounding stage of the reservoir following flood season. The results show that under the scour of river flow carrying little sediment at the impounding stage, the guard projects can significantly improve the waterways if certain conditions are met ？ shallow waterways are in a good evolution stage and the regulation targets don＇t differ much from their existing conditions. And adjustable regulation projects are needed to satisfactorily improve the conditions of those sections that are sensitive to the Three Gorges impounding stage following flood season.