Construction Mechanics And Numerical Simulation Of Subway Station Constructed By Top-down Method

With the rapid development of national economy and urbanization, urban traffic situation became worse. To solve this problem, building metro is an important method. This paper introduced the top-down method, which is an effective way of constructing subway station in the city centre. Its social and economic benefits have been widely recognized.In this paper, a subway station constructed by top-down method was molded by ANSYS software. The simulation of construction process and the dynamic time history analysis were carried out. So this paper mainly deals with the stress and deformation behavior of the subway station structure during the excavation and its dynamic response under earthquake. Some technical difficulties were solved during the study, for example, the setting of visco-elastic artificial boundary, the calculation of Rayleigh damping, the nonlinear contact of soil and structure. The main conclusions of this paper are as follows:During the construction, the diaphragm wall, column and horizontal plate may uplift and sink alternately under the influence of foundation rebound, gravity and construction load. The top-down method can control the differential settlement effectively. Under the influence of lateral soil pressure and horizontal plate, the horizontal deformation curves of the diaphragm wall was similar to bow at first and then to s shape. The huge horizontal stiffness of the plate can control the horizontal deformation of the diaphragm wall effectively. The most disadvantageous positions of internal force in each condition were shown finally. The dynamic response of underground structure was associated with the soil characteristics. The vertical earthquake can increase the axial force of the middle column significantly, and the shear resistance behavior of the column may be weakened. So the column would be more vulnerable to damage. The joints'internal force was larger than other positions', and the most risky component was the middle column, followed by the joint of the diaphragm wall and the bottom plate. These parts of the structure should be strengthened emphatically.