中文摘要：

以江苏沿海北部的射阳河闸下港道为原型,建立二维水动力及泥沙输运概化数学模型,模拟了淤泥质海岸闸下港道淤积过程。分别在不考虑径流年内分配变化和考虑径流年内分配变化的情况下,研究了入海径流对港道内水沙动力和冲淤演变的影响。参考前人研究成果,结合量纲和谐准则,根据模型的计算结果,建立了淤泥质海岸闸下港道年均平衡流量与汛期排水比例、河床断面积、外海潮差、潮波变形、港道长度等因素间的河相关系式,对在实际情况中达到动态冲淤平衡的某条特定港道,可简化为港道年均流量与河床断面积间关系式的简化形式,并通过分析实测资料,对公式的简化形式加以佐证。

英文摘要：

Taking a channel downstream the Sheyang sluice as a prototype,a two-dimensional generalized morphodynamic model is established to investigate the siltation mechanism of a typical channel downstream floodgate in muddy coasts,China. The influence of runoff on hydro-sediment dynamics,as well as the souring and silting evolution in the channel,has been explored with and without considering the change of annual runoff distribution,respectively. A semi-empirical equation describing the relation between the equilibrium discharge and the ratio of runoff volume in flood season,channel averaged cross-section,offshore tidal range,tidal wave deformation,channel length and other related factors is established. For a particular channel which is practically in dynamic equilibrium state of erosion-siltation,the above-mentioned equation can be simplified as a simple form of expression of equilibrium discharge and channel averaged cross-section. And the simplified form of this formula is validated by observational data.