Immersed Tube Tunnel In Zhoutouzui Stability And Maneuverability

Along with the continuous development of city traffic, immersed tube tunnel crossing therivers as another construction way sadly arisen, immersed tube technology has one hundredyears of development history, the construction of many problems have been overcome, butimmersed tube of floating, installation is still immersed tube tunnel technology the keydifficulty. This paper, from guangzhou state head nozzle tunnel project to, mainly around theproject immersed tube floating, installation construction stability and maneuverability insection on the analysis of the dynamic performance, for all kinds of adverse conditions how tocarry on the floating, installation construction to provide the reference basis for the wholeconstruction process of the characteristics and difficulties are summarized, and provide thecorresponding measures and countermeasures.Based on the development history of the immersed tube tunnel and all over the worldimmersed tube tunnel technical understanding, in similar construction conditions take thefloating, installation scheme for simulation, can determine the channel narrow, chau headnozzle used in the tunnel of the best floating, heavy put way is the shore winch hauling andtug pushing section floating method.In order to validate to use shore winch hauling and tug pushing section floating method tofloating pipe section stability, mechanical model was established, the section in theconstruction process of stress calculation and analysis, the main analysis section in floating inthe process of the kinematics and dynamics performance, including the determination of flowspeed, the section of the movement speed and heading, section of the floating body freedomof motion; Determination and calculation section on the surface of the water movement by allkinds of resistance (shape resistance, friction resistance and wave resistance, etc.), flowtransverse force and floating body metacentric height, determine the optimal floating state,best freeboard value and the required section drag resistance; Measurement section floating inthe process of the steel wire rope tension (towing cable tension, brake cable’s tension force,etc.), tug given section of the pushing force, analysis and adjust every wire cable tension andtension distribution balance, make section to the appropriate speed smooth movement; Foundthat influence immersed tube stability is the key to water resistance coefficient Cw, generalaccording to section of the shape and size, flow speed, floating route to the value range is verybig, in the favorable conditions for1.5, usually for3~4, especially adverse can reach six. Soin different water resistance coefficient, immersed tube stability change with it, according to the simulation software and the actual floating effect contrast found that Cw value of1.5themost close to the actual floating effect, and most can guarantee immersed tube in the processof floating stability.Research section in settling put, docking process accuracy control, including choose to suitthe project natural conditions and channel condition of heavy put scheme, section real-timepositioning measurement, section underwater attaches accuracy control. Through the tunnelprocess socket joint operation steps decomposition analysis, determine the union butt focusand difficulty lies in the union mooring, preliminary butt, pull close butt, stable ballast fourlink, and puts forward simulation union mooring test, and choosing the suitable heavy putopportunity, divers felt joint and corresponding solving measures. Through these measures,better finish immersed tube floating, installation process accuracy control.