山溪性强潮河口最大浑浊带形成机制及其模拟

Study on formation mechanism of turbidity maximum zone and numerical simulations in the macro tidal estuaries

为阐明强潮河口最大浑浊带的形成机制及其运动规律,通过瓯江和椒(灵)江实测资料分析,系统分析了强潮河口最大浑浊带形成的影响因素及其与河口地貌的响应关系。考虑黏性细颗粒泥沙运动特性和盐度的影响,开发了强潮河口最大浑浊带数学模型,对椒(灵)江枯季大潮最大浑浊带运移过程进行了模拟。结果表明:①强潮河口最大浑浊带是潮波变形、咸淡水混合、泥沙再悬浮等复杂因素在一定河口边界和泥沙条件下相互作用的产物,潮波变形和泥沙供给是影响最大浑浊带形成的关键因素。②强潮河口最大浑浊带模拟必须充分考虑潮流、盐淡水混合、泥沙周期性起动、絮凝和沉积密实等因素,所建立的数学模型可用于强潮河口最大浑浊带研究。

To illustrate the formation mechanism and movement characteristics of the maximum turbidity zone in the strong-tidal estuary,this study systematically investigated the main factors affecting the formation of the maximum turbidity zone and its response relationship with estuarine landforms in the well-mixed estuary by analyzing the measured data. By considering the effects of viscous fine sediment movement characteristics and the influence of salinity,this study developed a mathematical model of the maximum turbidity zone in the strong-tidal estuary,which was used to simulate the migration process of the maximum turbidity zone in the dry season of the Jiao (Ling) River. The results show that: the maximum turbidity zone in the strong-tidal estuary arises from the interactions of complex dynamic factors (e. g.,tidal wave deformation,saltwater-freshwater mixing,sediment flocculation and re-suspension) under certain estuary boundary and sediment conditions. Also,tidal wave deformation and sediment supply are the key factors affecting the formation of the maximum turbidity zone. In addition,this study revealed that simulations of the largest turbidity zone in the strong-tidal estuary should fully consider the all the factors,such as tidal current,saltwaterfreshwater mixing,periodic movement of viscous fine sediment,flocculation and sediment compaction. The mathematical model can be used to study maximum turbidity zone in strong-tidal estuary.