长江中游调关水道演变规律及趋势分析

Study on waterway evolution and changing trends of Tiaoguan channel in middle Yangtze River

通过实测资料系统分析了长江中游调关水道演变特点,重点对三峡蓄水后调关水道演变规律进行了分析,并研究了调关水道未来演变趋势。结果表明,调关水道河床由中细沙组成,河岸为粘性土和沙组成的二元相结构,河段自然属性较强,历史上河床在自然条件下主要表现为凹岸崩坍、凸岸淤长,弯顶缓慢下移。三峡工程运行后,来沙减少,枯水流量增加等因素影响,原淤积性凸岸发生冲刷,河道总体流速降低,且弯道进口区域由于凸岸冲刷,水流趋直,弯道环流作用减弱,导致了凹岸淤积。随着三峡蓄水后来沙持续减少,弯道段凸冲凹淤的趋势将会持续。

Through the measured data, the Tiaoguan waterway evolution characteristics, especially that afterthe Three Gorges reservoir impoundment, were analyzed. The future Tiaoguan waterway evolution trend had been re-searched. The results show that, Tiaoguan waterway bed is composited by middle and fine sediment. The river bankis composited by cohesive soil and sand. All these have made the river exist with a strong river natural property. Innatural state, the river evolution characteristics are shown as convex bank collapsing, concave bank sedimentationand the top of curved reach moving down gradually, with the effects of revetment and rocky node. After the ThreeGorges reservoir impoundment, the income sand reduced gradually and the low period discharge increased gradual-ly. As the scouring of convex bank, the flow rate decreased overall, flow lines turn straight and bend circulation de-creased. These made concave bank deposit. As the income sediment continuing decreased, convex bank collapsingand concave bank sedimentation evolution tend in curve reach would be continued.