Structural Analysis And Design Method Of The Soilless Cofferdam Structures Made By The Steel Pipes

Cofferdam is an essential structure for protecting the excavation scope of the foundation of tower structure in shallow water area. It has been used in the foundation with the development of the foundation technology in shallow water area. However, the traditional cofferdam construction has the disadvantages, such as earth and rock pollution, occupation of large area, poor waterproof performance and bad recycling. Thus, the design of the cofferdam structure should possess the functions of environmental protection, sustainable utilization, good waterproof performance and economic applicability for the tower foundation in the shallow water.In this thesis, a soilless cofferdam structure of the fundation of the 13# tower of the 110kV transmission line engineering from Chuzhou Dashan to Guhe is studied. The characteristics and constructive technology of related cofferdam structures are wildly investigated. The steel pipe type soilless cofferdam structure is applied to constructing of the tower foundation. Hydrostatic pressure and soil pressure are considered in the construction process of the establishment of the cofferdam structure. Then the stability and strength of the cofferdam structure are analyzed by the finite element method. According to the results of the stress and displacement fields of the cofferdam structure, the weak part in the structure design is strengthened by the optimized selection. The mechanical properties and rationality of the soilless cofferdam structure in the several different cases of water depths are evaluated through the results of the stress and displacement fields by finite element method.In the thesis, the complete design process of the soilless cofferdam structure, including stability, strength and economy analysis, is given through the theoretical calculation and implement of the 13# tower constuction. The research results of the soilless cofferdam structure made of the steel pipes can be acted as the reference for the structural design of the similar cofferdams.