波流联合作用下淤泥质潮滩泥沙运移过程研究

Sediment transport processes are an important part with associated with combined waves plus current situation in near-bed bottom layers. Recent years, under the influence of global climate change, rising sea levels and large-scale reclamations, how sediment transport in mud flat response has become the current multidisciplinary scientific issues. The typical mud flat is chosen in China—Zhejiang Oufei shoal. By employing advanced instruments to measure synchronous data including waves, current, suspended sediment concentration/grain size and bed level changes in the cross profile, and combined with the flume test. The bed shear stress, critical starting velocity and critical settling velocity under combined waves and currents are calculated. The morphodynamic model will be developed to study fine-sediment transport across mud flat. Therefore, the aim of the project is to analyze and quantify impact factors on transport rates and mechanisms for mud flat using a numerical model. This project will improve dynamic and geomorphology in estuary and coast, but also provide guidance to sustainable use in coastal engineering and tidal flats resource in coastal zone.

淤泥质潮滩剖面的泥沙运移是波流联合作用下近底边界层研究的主要内容。近年来，在全球气候变化、海平面上升以及大规模围垦等影响下，淤泥质潮滩泥沙运移如何响应已成为当前多学科共同关注的科学问题。本项目选取我国典型开敞性淤泥质潮滩—浙江瓯飞浅滩，利用目前国际上较先进的仪器，通过同步获取横断面上不同代表性部位的波浪、潮流、悬沙（浓度和粒径）、底床沉积物和滩面冲淤等第一性现场观测资料，结果物理模型试验，计算和确定波流联合作用下淤泥质潮滩的底床剪切应力、临界起动速度和临界沉降速度。建立淤泥质潮滩剖面的动力地貌模型，推算潮滩剖面的泥沙运移过程，寻求控制滩面冲淤变化的关键因子。此项目既有助于丰富河口海岸动力地貌学的理论和方法，又可为海岸工程和海岸带滩涂资源的可持续利用提供指导。

近年来，在全球气候变化、海平面上升以及大规模围垦等影响下，潮滩资源逐步丧失，但是潮滩泥沙的如何运移是当前多学科关注的科学问题。本项目以我国典型开敞性淤泥质潮滩—浙江瓯飞浅滩为研究对象，在潮滩上搭建试验观测平台，经过两个潮周期（14天左右）的观测获取横断面上不同代表性部位的高分辨率的波浪、潮流、悬沙浓度、底床沉积物等第一性现场观测资料，利用国际上通用的理论计算方法，计算潮滩上的波流联合剪切应力、临界起动速度和临界沉降速度等关键参数。建立淤泥质潮滩波流共同作用下的泥沙输移模拟系统，推算潮滩剖面的泥沙运移过程。结果揭示了波流共同作用下，潮滩上的泥沙更容易启动，潮滩上含沙量由增大趋势。