Formation And Revolution Analysis And Related Two-dimensional Tide-sediment Numerical Simulation On Radial Sand Ridges In Northern Jiangsu Province

The unique terrain of radial sand ridges in the southern yellow sea is located in the area beyond the coastline of northern Jiangsu province with a water depth bellow 30 m.Shaped by radial tidal current which takes Jianggang as center,the radial sand ridges is the most distinctive offshore tidal depositional system.Complex tidal current and instant deposit and erosion of silt sand in radial sand ridges make its water dynamics and sediment environment fairly complex.Therefore,necessity exists to make detailed research on the process of formation and development in this area.Moreover,the need of local development makes it urgent to have a new large port in this area.Steady condition of tidal current and water channel in the south edge of radial sand ridges also makes it feasible to construct ports alone ridges there.In order to assess the effect of reclamation and port construction project in such area on the local water dynamics and sediment environment,it is necessary to carry out numerical simulation on local tide and sediment environment in this area,and analyze the effect of long-term planning on local tide hydrodynamic characteristics.This thesis determines to analyze the development history of the radial sand ridges in a macro perspective,and summarize its formation causes.Also,with a port construction plan of Nantong,a two-dimensional hydrodynamic and sand deposit model is used to simulate tidal current and sediment transportation and figure out the difference of hydraulic and sediment environment before and after the port construction in this thesis.Effect on hydraulic and sediment environment caused by port construction then can be outlined to verify the practical feasibility of the construction project.Analysis on history evolution and formation mechanism of radial sand ridges describes local geomorphologic conditions and shows certain reference value in this thesis;Numerical simulation outcome points out that the construction project will definitely cause obvious changes in local water dynamics,but merely affect tidal environment in large scale.Sediment deposit among port area comes within an acceptable area.