Research on Mechanical Characteristics of Segment Joint Shear Keys of Immersed Tunnel by Three Dimensional Numerical Method

Based on the finite element software ANSYS,adopting contact elements at segment joints,utilizing double line elastic link elements,which can be only compressed,to simulate rubber pads,the three dimensional and numerical model of segmental immersed tunnel was constructed. The longitudinal bending and twisting working conditions of immersed tunnel under uneven load and settlement conditions could be simulated,by means of adjusting the elastic modulus and Poisson ratios of soil layers under the immersed tunnel. In addition,through analyzing characteristics of stresses and shearing forces on segment joint shear keys,the mechanical capacity of these keys was studied.Finally,the numerical results were compared with the results of large scale model test. The main conclusions are that,vertical shear keys which undertake most vertical shearing force have barely contribution to horizontal shearing resistance. However,the horizontal shear keys have horizontal shearing force in all these conditions. The shearing force of vertical shear keys on the side of soft layer is bigger than that on the side of hard layer. Furthermore,partial stresses on tips and connection areas of shear keys are significant.