The Numerical Simulation Of Water And Sediment Environment Of A Nuclear Water Intake Project On Huanghua Port

The sediment of Huanghua port,as the representative of silty coast,has the characteristics of small starting velocity,large settling velocity.Besides,during the gale weather,the sediment movement is pretty active,which used to cause the siltation in the port and waterway.It is planned to build some water intake projects,such as nuclear power plant intake,at the end of the first harbor basinof the comprehensive port.To a certain extent,the project may change the hydrodynamic and sandy environment,which could also be influenced by the nearby sediment field caused by the storm surge.As a result,the main emphasis of research is the sediment problem near the water intake,and the main research contents and results are as follows:(1)Based on the existing research of the Huanghua port sediment characteristics,the coupled model of wave and sand flow is established by using MIKE21/3hydrodynamic,sediment and wave modules,and the effects of wind surge and wave breaking are taken into account.The model is verified by using the the existing statistical material of the testing data.(2)Based on the model,the flow-sediment environment surrounding the port structures in both normal and storm surge weather is simulated.The results shows that the amount of the sediment entering the port area under the E-direction storm surge is lager than that under N-direction wind.During the storm surge,the stretch of the jetty,which can keep water and silt away,effectively reduces the sediment transported to the entrance.Equipped with the small entrance and large abdomen,the comprehensive port effectively prevents the sediment from entering the entrance.Also,the ebb tide can bring out some sediment that has already entered the entrance.The dredged harbor basin and long channel could be equivalent to a large silting basin,which made the water power,sediment content and silt thickness decrease from the entrance to the inner of the harbor basin.The sand content of one harbor basin is extremely low.Water inflow into the surface of one of the harbor basin terminals,and outflow from the bottom,which helps the sediment transport outward.These buildings’effect confirms the rationality of the water-intake site selection.(3)The implementation of the water intake project accordingly increase the sediment-water mixture entering the terminal of the harbor basin.The sediment silts at the front of the intake.Besides,with the increase of the intake flow,the thickness and range of sediment deposition also increased.After analyzing the sediment silting velocity in front of the intake,it is found that the water intake connects the main stream and sediment continuously transport into the intake when the flood,while the water intake isolated from the outside current and sediment intensively deposit at low tide.(4)The other factors of the incoming sediment in front of the intake are analyzed as follows:There is no effect on the intake that the sand-lifting caused by the 100thousand ton ship’s propeller,650 meters away from the intake.The annual deposition thickness before the intake is calculated to be 0.016m under the action of constant wave.After a once in-fifty-year storm,the sediment concentration of the intake reaches 0.11kg/m~3,with the deposition thickness of 0.07m.After a once in-fifty-year storm,when considering the sediment overtopping in the F2-F3 section of the breakwater.the sediment concentration of the intake reaches 0.3kg/m~3,with the deposition thickness of 0.32m,which is far less than the reserved safety elevation,and the water intake can be operated safely.