| This paper mainly in the Chongqing area of a South Z09# main pier of double wall steel cofferdam with high sinking construction process engineering background.The south tower foundation located close to the South Bank of the waters,from the planning channel edge is about 30 m,the Three Gorges reservoir when water depth is about 53 m.This double walled steel cofferdam is designed with high 57.809 m,the diameter of which is 47.2m,the diameter of which is about 43.2m.The main pier platform is round,with a diameter of 43 M,thick 8m,and the top surface elevation of the pile cap +139.760.Concrete concrete C40,the number of fand 11617.6m.The Three Gorges Reservoir area,flood compensation regulation effect in the bridge area year water level reached 30 m.Impounding water level is higher,up to 174.22m(Yellow Sea elevation)and low velocity,generally at about 0.5m/s;fluctuating period,the water level is low,to the lowest 143.76m(Yellow Sea elevation),maximum flow rate of up to 2.6m/s;20-year flood water level for 164.884 m,velocity 2.0m/s.Steel cofferdam in the height direction is divided into 9 sections,respectively,2 sections of the foot section,section 4,Section 2 and section 1 section of the standard section of the section.Each segment is divided into 12 ring block(the foot blade section I type is divided into eight ring block),which I edge foot tall 3.2m ~ 9m,high foot blade segment II 4.79 m,strengthen section height in order to 6m,6m,6.4m and 7m,standard height is 6m,cofferdam top height is 6.619 m.The structure characteristic of double wall steel cofferdam is introduced in this paper.It is pointed out that the double wall steel shell with high strength can bear the difference of inner and outer head.In cofferdamming before the simple procedure,plus cofferdam reserved hole,can be back as soon as possible to flood safety.Therefore,the construction of pumping water and flood water effects were not affected by the construction,can carry out construction operation in any season.Double wall steel cofferdam than the steel sheet pile cofferdam,simplify the construction process,shorten the construction period,there is a big breakthrough.The main research work of this paper is as follows:(1)this paper with a double wall self floating ground high sinking scheme as the research background,using the finite element software ANSYS,the actual construction of simulation analysis,double wall steel cofferdam of Deepwater Floating ground high sink process component stress and stability analysis of,and determine the feasibility of construction scheme,for double wall steel cofferdam in actual engineering construction scheme provides the theoretical basis for design and calculation.(2)give full consideration to the compartment and water head difference between the effects on load carrying ability and stability of each component of the cofferdam,through the analysis and calculation for precise positioning of the cofferdam is easy to deformation and instability of the internal components,which can be welded in the cofferdam design and construction process of this segment by force weak parts of special strengthening;and in the decentralization of construction process is for commissioned monitoring of stress state is dangerous section should stress state control in order to ensure the safety and controllability of underwater cofferdam construction process.(3)by Chongqing area a South Tower Z09# main piers of double wall steel cofferdam of high sink during construction of cofferdam under hydrostatic pressure,gravity,buoyancy effect by force performance,the analysis of the regulation of every class head difference on the importance of construction safety assurance.Some suggestions on the design of double wall steel cofferdam are put forward through the research and analysis. |
PDF Full Text Request