Monitoring And Numerical Simulation Of Urban Subway Constructed By Top-down Method

Abstract:With the rapid development of national economy and urbanization, urban traffic situation became worse. To solve this problem, building metro is an important method. It has a positive significance to research the top-down method, which is an effective way of constructing subway station in the city centre.By the observation of Bayi museum station, Block5, Nanchang Subway Line1, combined with the actual construction situation, this thesis carries out the research mainly on the aspects of field monitoring and finite element numerical calculation. The main work of this thesis is dealt with three following respects:(1) Through the scene monitoring and measuring of the Bayi museum station construction process, this article analysis the deformation of foundation pits of the top-down method construction process. Verify that the envelope design is reasonable and safe, and verify the feasibility of top-down method in Nanchang region.(2) Simulated Bayi museum station top-down method construction process dimensional finite element static model, contrasting monitoring results with the finite element results, to verify the feasibility of the model, analyzed numerical results, researching on the underground structures force and deformation of the top-down method construction process.The conclusion will be getting:the monitoring results are consisten with the finite element results. High stability of foundation pit surrounding soils. The horizontal deformation curves of the diaphragm wall was similar to polyline shape. The huge horizontal stiffness of the plate can control the horizontal deformation of the diaphragm wall effectively.(3) Establishing the three-dimensional dynamic analysis model when the upper road vehicle dynamic load act on the Bayi museum station, research the dynamic response results of the covered excavation station. The conclusion will be getting: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.