长江张家港老海坝段水动力及冲刷分析研究

Study on hydrodynamic characteristics and riverbank scour along Laohaiba reach of the Yangtze River

老海坝位于浏海沙水道主流顶冲岸段,河岸稳定备受关注。文章在分析老海坝河段历史演变的基础上,利用一、二维耦合潮流数学模型,模拟计算不同水文条件及人类活动下老海坝河段的水动力特性,分析对河岸冲刷的影响。研究结果表明：（1）历史上老海坝是人工形成的节点,具有可冲性;（2）老海坝沿岸的水动力受自然条件和人类活动影响,自然条件下沿岸最大流速出现在大流量落潮条件下;（3）双涧沙工程实施后,近岸流速有减小的趋势,减小幅度在0.01~0.03 m/s;（4）老海坝近岸流速沿程增加,进口流速小,出口流速大,输沙不平衡,河床处于冲刷状态。随着河床的冲深,水沙条件将重新达到平衡。

Laohaiba reach lies in the segments of mainstream scouring of Liuhai shoal waterway, and particularattention has been paid to the bank stability. Based on the analysis of the historical evolution of the Laohaiba reach,the hydrodynamic characteristics under different hydrological conditions and human activities were calculated byuse of tidal current model. The impact of hydrodynamic characteristics on the bank erosion was also analyzed. Theresult shows：（1） the Laohaiba reach is an artificially created node in history, and it is erodible.（2） Hydrodynamiccharacteristics along the Laohaiba reach are determined by natural conditions and human activities and the maxi-mum velocity occurs under the condition of large flow in the ebb period.（3） After the implementation of the Sh-uangjiansha shoal protection project, nearshore velocity tends to decrease, and the decrease extent is between 0.01 and 0.03 m/s.（4） The nearshore velocity increases along Laohaiba reach. The inlet velocity is small and the outletvelocity is large, leading to the sediment transportation imbalance and the riverbed being on the scour status. Withthe riverbed scouring depth, water and sediment condition will become balance again.