Deep-water Bare Rock Pile Foundation Construction Platform Structure Analysis And Construction Technology Research

Combining with the construction for the high-rise pile cap foundation of bored pile of the main bridge of Qianjiang Super Large Bridge, the paper has firstly summarized the commonly used types of construction platform. Then, with the characteristics of high flowing speed, irregularly fluctuant water level and rapidly changing water level under heavy precipitation, a steel pipe pile platform construction scheme was rafted. Finally, the simulation analysis of structural mechanics of the platform was done to make further discussions on the structural stability. In general, the following specific works have been accomplished:1. Through analyzing the commonly used type of construction platform as well as its natural environment to be adapted to, and meanwhile considering the project’s characteristics like uncovered rock, deepwater and rapids, etc., a preliminary design scheme of the stent platform in steel pipe pile was rafted.2. MIDAS/Civil was used to construct the whole model of the rafted platform, do performance simulation analysis of structural mechanics and test strength and stiffness of the platform structure.3. On the basis of theoretical analysis of linear elastic and nonlinear, four finite element models of steel pipe piles under different boundary conditions were established to investigate the effects of different theories and different support conditions to the component stability performance.4. Based on the analysis of the effect of the boundary conditions to the ultimate bearing capacity, idea of changing the boundary conditions of the steel pipe piles through controlling of the overall displacement of the platform was proposed. Taking into consideration of the definition of non-support and support frame in Code for design of steel structures to optimize the preliminary design scheme and construct the construction collision piles in advance. Consequently, the overall stiffness of the platform was enhanced and the ultimate bearing capacity of the steel pipe pile was improved.5. To deal with the construction problem of drilling on the bottom of piles under deep water and uncovered rock conditions, the bolt anchoring method was adopted. For the steel casing construction problem of crash pile, an improved program about sinking the steel casing to crank down the hole after water drilling was posed, which can effectively reduce the workload and improve the progress of the project.