长江口北槽悬沙输移机理分析

Mechanism of Suspended Sediment Transport in the North Passage of the Yangtze River Estuary

运用通量机制分解法对长江口北槽深水航道的实测水文泥沙资料进行了分析,将悬沙通量分解成了8个动力项,从平流输沙、潮泵效应输沙和垂向净环流输沙三方面综合分析了长江口北槽的悬沙输移特征。研究结果表明:在水文资料实测年份时,北槽输沙主要来源于上游来沙;平流输沙项占总体净输沙的比重最大;潮泵输沙所占比例较小;航道内的各测点的垂向净环流输沙主要受欧拉余流控制;深水区悬沙含量垂向变化明显,河口浅水区,表底余流方向不同,垂向净环流输沙作用增强。

The mechanism decomposition method is used for calculating the water and sediment date,the sediment flux has been divided into 8 dynamic items,the characteristics of the suspended sediment transport have been illustrated through exploring the mechanism of the advection,tidal pumping effects and the vertical circulation for sediment transport.The results show：in the year of the hydrological data measured,most of the suspended sediment in the North Passage of the Yangtze River Estuary comes from the upstream regions.The advection is the main factor to affect the suspended sediment transport.The tidal pumping effect plays a minor role.In the channel,the vertical circulation for sediment transport is mainly controlled by the Euler residual flow.The vertical sediment concentration changes significantly in the deeper region,the residual current directions are inconsistent in different vertical layers in the shallow estuary region,the vertical circulation plays a stronger role in the shallow regions.