中文摘要：

针对外秦淮河入江口的三汊河河口闸大流量泄洪时过闸水流不均的问题，建立了江河水闸大范围水深平均二维数学模型来研究河口闸的泄流特性，并利用河工模型试验结果率定模型参数。对长江不同水位流量组合及河口闸上游河床地形修整工况下河口闸大流量泄流特性模拟计算结果表明，导致过闸水流不均的主要因素是河势及河道深泓位置；河口闸上游阻水建筑物的拆除对过闸偏流的改善作用有限；37m墙长结合5毅偏角的导流墙可有效改善过闸水流不均的现状。

英文摘要：

In order to deal with the deflection of flow passing through the Sanchahe River Gate, which is located at the conjunction of the external Qinhuai River and the Yangzte River, under large discharges, a two-dimensional depth-averaged mathematical model was developed to investigate the discharge characteristics. Experimental results from river models were used to calibrate the model parameters. Several typical operating conditions, including different combinations of the water level and the discharge of the Yangtze River and the correction of the upstream riverbed topography, were studied. The numerical simulation results show the following：the main reasons for the serious deflection of flow are the river regime and the location of the river thalweg; removing the water-blocking facilities upstream of the gate has limited influence in improving the pattern of flow passing through the gate;a guide wall with a length of 37 m and a deflection angle of 5o can improve the pattern of flow passing through the gate significantly.