Research On The Construction And Supporting Technology Of Large Scale Caisson In Deep Water With High Flow Rate

Our country has numerous rivers and vast sea areas. With the bridge construction developing towards to the wide water area and open seas, more and more super-large bridges across rivers and straits are built up. In construction, with more complicated geological conditions and increased depth of water, the demand for bridge foundation is becoming higher and higher. Therefore, large-scale caisson foundation in deep water has appeared and it brings more technology challenges to bridge construction. At present, domesic technology materials of this kind of foundation is deficient and many new technical problems will show up when the construction is in progress, so we need to learn from foreign advanced achievements and technology and the learning should be carefully combined with the domestic actual situation and specific bridge projects. Beased on Hu Tong Railway Bridge project, this thesis scientifically studies the construction arrangement and the key construction technology of large-scale deepwater caisson foundation.This thesis is divided into six parts:The first chapter introduces the purposes and contents of the topics and reviewes current development of large-scale open caisson in deep water with high flow rate. The engineering background of Hu Tong Raiway Bridge is also described.The second chapter elaborates the technology and quality standard of open caisson manufacture. The selection of different ways to put the caisson into water, the aid-floating plans and the float-conveyance technology is also discussed.The third chapter introduces open caisson positioning system. A new integrated positioning system called "steel anchor pile and gravity anchor" is proposed, which is more accurate and easily to operate. Its innovation lies in that the position of the cable fixed on the main anchor is above the river surface and the free cantilever length of the steel anchor pile is greatly reduced, thereby reducing the size of the steel anchor pile and the investment.In the fourth chapter, the caisson sinking technology including the caisson sinking calculation, the caisson sinking construction method, the caisson suction sink and the caisson positioning onto riverbed is elaborated.The fifth chapter mainly researchs on the technology of concrete caisson site jointing. Combined with caisson sinking, the allocation of form work for site jointing is analysed and the order of concrete caisson pouring is studied.The sixth chapter is the conclusion. A brief summary is made and the continue work in the future is introduced.