Research On Multi Degree Of Freedom Coupling Mechanical Model Of Shield Tunnel Joints

In this paper,a multi-DOF coupling mechanical model is established for the multi-DOF coupling deformation of the shield tunnel joint.On this basis,a finite element numerical experiment is carried out to verify the feasibility of the multi-DOF coupling joint mechanical model.Then,the application of the multi-DOF coupling joint mechanical model is studied.A nonlinear mechanical model and its numerical calculation method are studied to reflect the coupling deformation characteristics of the shield tunnel joint.Finally,the transversal seismic nonlinear response of the shield tunnel is analyzed.The main contents and conclusions of the paper are as follows1.The displacement-based mechanical modeling method is introduced to the mechanics modeling of joint.The method takes displacement as the known quantity,and solves the contact state by assuming the deformation function,and finally calculates the external force and the internal response of joint.The assumption of rigid plate is put forward,and is preliminarily verified by the finite element numerical calculation.2.By assuming deformation of joint as the deformation function of the rod and beam,the mechanical model of concrete without shear is derived.Then,the deformation of concrete with shear is decomposed into no shear deformation and shear deformation,and the mechanical model of the concrete with shear is derived.Also,the mechanical model of joints with slip are derived.These results are preliminarily verified by finite element numerical experiments.3.The multi-DOF coupling joint mechanical model is put forward,and the mechanical model of joint with or without slip is given,and its feasibility is verified by finite element numerical experiments.The mechanical model of the ring joint is preliminarily studied,the mechanical model under 4-DOF and 3-DOF is proposed.Considering the gaskets and sealing strips,a preliminary equivalence plan is proposed.4.Based on coupling joint mechanical model,the parameter calculation of joint stiffness matrix element,spring element and equivalent beam element,and two kinds of nonlinear structural models are presented,the calculation algorithm is given.The analysis of the transversal seismic nonlinear response of the SHIZIYANG tunnel,based on the response displacement method,shows that the distribution of structural internal force with the coupling mechanical model is basically the same as that of the equivalent continuous beam model,but the results of the coupling mechanical model show that the most unfavorable position of the shield tunnel is the joint,which is more in line with the actual situation.