汉江下游干流受顶托影响河段蓄泄能力研究
Study on Storage and Discharge Capacity of Main Stream Affected by Backwater in Lower Reaches of the Hanjiang River

汉江干流上中游河段洪水来量大，中下游中干流河道河槽泄流能力小，其中仙桃以下的干流河道泄流能力与长江干流顶托影响密切相关。本文采用河道槽蓄量分析方法分析了汉江下游干流泽口~仙桃河段受到汉江下游顶托影响下的槽蓄曲线特征，并结合平面二维水流数学模型分析了汉江中下游仙桃以下干流河段受顶托影响下水动力特性，揭示了汉江上游来水较大情况下下游段受长江干流的顶托影响程度。研究结果表明：汉江下游河段由于受到两岸堤防约束，河道槽蓄能力有限，在遇到长江干流高水位顶托时，会显著减小下泄流速，与不顶托的情况相比，河道内最大流速量级可由3 m/s减小至1.2 m/s，受顶托严重时会明显抬高仙桃河段的洪水位，水位抬高值可达到2 m左右，对汉江中下游两岸堤防稳定和下游防洪安全产生较为不利的影响。
There are a large amount of flood in the upper and middle reaches, and small discharge capacity in the middle and lower reaches of the Hanjiang River. The discharge capacity of the main channel below Huangzhuang is closely related to the backwater effect of the Changjiang River. In this paper, channel storage analysis method is used to analyze the characteristics of channel storage curve from Zekou to Xiantao under the influence of the lower reaches of the Hanjiang River. Combined with the two-dimensional flow model, the hydrodynamic characteristics of the lower reaches under the influence of the upper reaches of the Xiantao are analyzed. In case of large inflow in the upper reaches of the Hanjiang River, the influence degree of the backwater of the lower reaches of the Hanjiang River is revealed. The results show that due to the embankment constraints on both sides of the lower reaches of the Hanjiang River, the channel storage is limited, then the high water level backwater of the mainstream of the Changjiang River will significantly reduce the discharge velocity and raise the flood level of the downstream channel, which is unfavorable to the flood control of the middle and lower reaches of the Hanjiang River.