Research And Analysis On Key Technology Of Immersed Tunnel Engineering

With the rapid development of China's economy and urban and inter-city traffic,new requirements have been put forward for the design and construction of transportation and transportation systems across the river and bay areas.At present,the world a large number of cross-estuary,cross-bay major channel projects have been brewing the way through the immersed tunnel,Europe and the United States and Japan have a lot of successful application of immersed tunnel example,China's Shanghai,Guangzhou and Ningbo and other regions also built Immersed tunnel.Although the immersed tunnel has developed rapidly in China,but the domestic immersed tunnel started late,many technologies are not yet mature compared with foreign countries,and the construction of immersed tunnel project is a huge,complex and arduous task,involving many disciplines,many key Technology is not yet perfect,the engineering staff to participate in the technical and management requirements are relatively high.Therefore,we must in the immersed tunnel tunnel construction process,continue to sum up,accumulate construction experience,to ensure the smooth construction of the project.A domestic immersed tunnel built in the river upstream of the immersed tunnel,but also highway and subway construction immersed tunnel.Due to special geographic environment and construction conditions,the tunnel construction process technology used in the country has been immersed tunnel built more different.Based on a wide literature and research results immersed tunnel project basis,to the immersed tunnel as the research object,studied to optimize the immersed tunnel construction process in key technologies.The main work and conclusions are as follows:1)to study the development of immersed tunnels at home and abroad,summarize the advantages and disadvantages of immersed tunnel according to the development situation;2)According to the immersed tunnel works at home and abroad,The key process to carry out research,summarize the key construction process used in the construction process,put forward the advantages and disadvantages of the construction process for the future construction of immersed tunnel tunnel project reference;3)analysis of a domestic immersed tunnel project dry dock,pipe prefabrication And the key construction technology of the process such as base trench excavation,pipe floatation and pipe foundation treatment,and study the difficulties in the construction process and put forward the countermeasures.4)Study on the floating and steady state of the floating stage of the pipe section The results show that the ballast water level of the pipe section has a certain influence on the center of gravity of the pipe section but the influence is small.The ballast water level should be arranged symmetrically as far as possible.Symmetrical pumping and the pipe section should try to choose a large freeboard value pipe metacentric height high initial stability while taking measures to ensure the best protection pipe in the design and construction;5)of the pipe in water and soil for load The pipe stress,displacement analysis,the results show a greater tensile stress in the wall and roof junction,should be arranged in the tension zone suitable reinforcement strength,tensile and flexural meet the requirements.Side wall and pipe roof area to produce a greater compressive stress,pressure area should be increased in the amount of reinforcement.The pipe section of the project belongs to the asymmetric structure,and the stress plays a role in controlling the symmetry of the pipe section.But the asymmetric part of the pipe will lead to both sides of the uneven deformation is more obvious.So in the pipe design and construction to take measures to eliminate such adverse effects.The research and analysis carried out in this paper can provide reference for the later immersed tunnel project,which has theoretical and practical significance.