Research On Mechanical Behaviors Of Segment Joint Of Railway Sheild Tunnel

In the various shield tunnels, it is vital to design and research of segment joint for its unique and complex structural characteristics. The joint bending stiffness, which synthetically reflects the mechanical characteristics of segment joint in shield tunnels, as well as its magnitude and trends of deformation under the external loads, is mainly obtained by experience-analogy and segment joint proto-test, not existing formulations or graphs to use.Based on Shiziyang underwater railway shield tunnel engineering, to combine Scientific Research and Development Projects of China's Ministry of Railways, this paper focuses on mechanical characteristics of segment joint, adopting mainly the segment joint proto-test supplemented by the numerical simulation and calculation. The major work in the paper is listed as follow.Loading test and destruction test are applied on the prototype segments according to the joint type of Shiziyang underwater tunnel so as to study the bending capacity of the longitudinal joint. All these jobs are for the purpose of achieving the actual mechanical behaviors of segment joints.The segment near the joints is selected to build the three dimension finite element model. Besides, the pre-tension of the bolts are taken into consideration to get some preliminary results of the dislocation and open angle of the segment joints, which are key factors to research the joint's mechanical characteristics. Some proposed joint stiffness is given according to the simulation results along with the conditions of Shiziyang underwater tunnel.Beam-spring model is applied under load-structure model in the calculation. Through the simulation we can get the changing law of bending moments, axial forces and deformations under different joint stiffness to analyse the influencing that joint bending stiffness caused to structure inner forces, hoping to provide references to set the value of stiffness in realistic engineering design.