The Seismic Responds Analysis Of Tianjin Station Transport Junction Considering The Soil-structure Interaction

With the development of the urban rail transit, all types of transport connections and the change of the station building are developed rapidly. As a project supporting of the Beijing Olympics and "Eleventh Five-Year Plan" key projects of Tianjin, Tianjin Station transport junction need all aspects of studying on the structures. as an important component of the Lifeline works, the seismic of the transport juction has become a important issue of the city earthquake engineering and earthquake disaster prevention.The main achievements of this dissertation are described as follows:(1) Tianjin station transportion junction was reasonable simplified. The floor of the underground structure was regarded as a infinite stiffness flat in its own plane,and the ground structure is regarded as a beam-column system.The nonlinear constitutive models and the element in the finite models of soil and building were chosed;the two-dimensional and three-dimensional viscoelastic artificial boundary were realized in the ANSYS Program. The soil-structure interaction analysis of dynamic finite element model was established and the dynamic time history analysis method was determined.(2) In order to reduce the computation the pile-soil region was regarded as a equivalent composite material model.the pile-soil cell finite element model was establised to simulate the destrction of the small size components, and the elastic constants of the composite material model were attained. Select shear stress -strain constitutive relation was chosed to regard as the material constitutive relation of the composite material model.(3) The structure-pile-soil finite element model of two typical cross sections of the Tianjin station Transport Junction were established and the seismic responds of the whole system under three different seismic load was attainted. Comparing the result of the seismic responds with the rigid foundation model, the result shown that the frequency of the rigid foundation model is greater than the soil-structure interaction system, and the soil around the structure is easy to be plastic,and has some effect on the seismic responds.(4) The three-dimensional dynamic analysis model of the Tianjin transportion model was establised and the seismic responds under three different seismic waves were calculated and some conclusions were got. The seismic responds of the transport junction under Tianjin seismic wave were the greatest. The displacemet responds norms are less than the limit. The accelaration and displacment responds of the ground structure is greater than the underground structure, particularly for the top of station of the ground struction. The interal force of the column top on first floor and the column footing on third floor were comparatively large. This weakness of the structure should be payed more attention on them.