Immersed Tube Tunnel Segment Joints Shear Force Characteristics And Mechanism Of Action

As the more immersed tube tunnels continued to be built in our country, the immersed tubeconstruction method get enough attention. The theory and technology are continuous improvement. Thecurrent construction of over length immersed tube tunnel often use sectional tube to replace integral tube,to avoid concrete cracking due to change in temperature, differences in construction, the internal stress inconcrete excessive. Experimental study at home and abroad mainly for the immersed tube tunnel in themiddle and final joints, while research in the aspects of the form, mechanical characteristics, mechanismof action and shear bearing ratio in segmental joints is still little. In this paper, it depends on the HongKong-Zhuhai-Macao undersea immersed tube tunnel project. Researching the form of destruction, thereason of destruction, the development trend of stress, analysis of dangerous sensitive area and themechanism of the shear use the measure of theoretical research, three dimensional numerical modeling, thelarge scale model test on loads under extremely adverse circumstances in a comprehensive.Firstly, before the model test, determined in accordance with section immersed tube tunnel sufferedmajor loads caused by differences in the longitudinal stiffness and uneven ground back silt load conditionsand lateral bending stiffness differences and uneven ground back silting caused by tensional load conditions.Establishing full-scale three-dimensional numerical simulation to simulate the actual project, analyzing themechanical properties of the immersed tube segment joints and provide guidance for the physical modeltests.Secondly, based on subgrade settlement platform of Chang’an University, according to testrequirements for platform reconstruction, carried out the overall program implementation model tests interrestrial conditions surrounding the sinking pipe section and the soil structure interaction scale model of alarge majority tests and experiments to solve the technical problems encountered. Numerical simulation ofreduced scale model tests to establish a fully simulated and compared the results of research and analysismodel tests, to establish a bridge between the reduced scale model tests and numerical simulation.Thirdly, the use of the means of combine reduced scale numerical simulation and model test,elaborate section joint shear key failure modes in bending and torsion conditions, damage causes stresstrends danger of shear key sensitive areas for analysis and proposed should focus on strengthening theshear key areas, and finally from the comprehensive aspects reveal the mechanism of the shear key, therelevant conclusions have a certain significance on the proposed construction of undersea immersed tubetunnel engineering design and research.