Analysis Of Construction Technology Of Marine Large Diameter Bored Pile

Cast-in-place pile foundation is widely used in our country. Because of its advantages of large capacity, fast construction and cost saving, bored pile has also been adapted to the deep foundation construction. China has long coastline and numerous coastal islands that have development value, so it is be imperative to build larger sea bridge. However, the construction of cross sea bridge in China has just started, the practice of offshore foundation construction is not yet mature, the project in the construction is also less. Therefore, the cast-in-place pile construction is facing new challenges--namely, the large diameter bored piles at sea.High tides, strong wind and big waves of the ocean and large horizontal force brought many new problems to the sea bridge construction especially foundation construction. Secondly the higher requirements for the structure durability of marine bridge brought trouble to the construction. The ocean climate causes short-term and uncertainty of offshore construction, which also caused difficulties in construction. Due to the above reasons, the difficulty of construction of bored pile in marine environment is more prominent than that in the other conditions. This determines the content of this thesis, the key construction technology of large diameter bored piles in the marine area.This paper, combining with the construction of bored pile in a project of island conjunction bridge, firstly, the characteristics and construction technology of offshore construction platform is expounded. Then, aiming at the steel temporary bridge erection, platform construction, steel tube processing and installation, mud configuration, impact hole, reinforcement cage, concrete pouring process, the paper analysed the construction features of bored pile has been analysised, put forward the existing difficulties in the construction of offshore Large Diameter Bored Pile. Reasons have been analyzed, the solution was prepared, and then the paper describes the key technology of construction.According to the problems in the construction process, the problems of hole collapse, inclined holes, reaming and shrinking hole, reinforcement cage floating, pipe engineering problems in the construction process of Bored Piles in sea have been given optimal solutions, and two accident cases and solutions have been provided. Finally, considered the sea current, wave, tide load on pile foundation as well as the impact of temporary construction structure, numerical simulation is carried out using the finite element software to do the safety check of the drilling platform.Experience of sea large diameter bored pile construction technology will promote the application of bored piles, will also accumulate experience for offshore bridge foundation construction to promote the further development of offshore foundation engineering.