Research On Key Technologies Of Floating And Sinking Of Immersed Tunnel For Hong Kong-Zhuhai-Macau Bridge

With the acceleration of the global urbanization,the traffic and transportation system is required to be improved inevitably.The underwater tunnels can well solve the problem of water crossing and reduce the impact on the surrounding environment,which will not affect the shipping.Therefore,the underwater tunnel construction in the rivers and straits increases unceasingly.Because of the unique advantages in economy and technology of the immersed tunnels,and with the key technical issues in design and construction of the immersed tunnels becoming more sophisticated,the immersed tunnels have been paid more and more attention by more and more countries.It has become the first choice construction method of the underwater large tunnel project.The technology of immersed tunnel abroad is more mature.Despite its late start,China is making rapid progress.Some immersed tunnels,such as Guangzhou Zhujiang Immersed Tunnel,Ningbo Yongjiang Immersed Tunnel and Shanghai Outer Ring Immersed Tunnel,have been built in recent years.The ability of independent design and construction has been initially available.In the project of Hong Kong-Zhuhai-Macau Bridge Immersed Tunnel,there are many new technical problems on floating and sinking of the immersed tubes under the ocean currents,waves and other marine environment.In this paper,the whole numerical model is established to simulate the floating and sinking of the immersed tubes in conjunction with the project of Hong Kong-Zhuhai-Macau Bridge Immersed Tunnel.The research on hydrodynamic performance of immersed tube floating resistance and sinking,which provides necessary theoretical guidance for the construction of Hong Kong-Zhuhai-Macao Bridge Immersed Tunnel project.The whole project includes the pipe-section floating condition,sinking waiting and sinking condition.The calculation includes CFD resistance analysis,bending moment analysis,cable system stress analysis,floating body motion response,etc.The SESAM,including HydroD,DeepC,SIMO,and Fluent,OrcaFlex etc.are used for numerical calculation.The main research includes:(1)Hydrodynamic performance analysis during the process of the floating,including resistance and bending moment of immersed tubes,etc;(2)Hydrodynamic response analysis of the immersed tubes under the current,wave and wind during the process of sinking waiting;(3)Simulation analysis of the immersed tubes sinking under current;to forecast immersed tubes sinking process posture and evaluate the credibility of the project.