Study On Surrounding Environment Influence Caused By Metro Hub Construction In Shenzhen

With the rapid development of urban area in China, many cities have already been suffered from traffic jam and this problem brings a lot of inconvenience to our daily in Chinese city. Many first-tier cities, such as Peking, Shanghai, Guangzhou, Shenzhen and Wuhan, have constructed several subway line and their subway system have been a certain scale. Cases in these cities can certify that metro is a good way to solve city traffic jam and to improve people’s travel quality. However, with the continuous construction of metro, subway network will be more and more intensive in cities. The amount of cross transfer station will increase sharply when new constructed metro lines cross with existing metro lines or other new constructed metro lines. Several large scale cross transfer subway stations have already been built in big cities such as Peking and Shanghai, however, the only experience that was concluded from the several large scale metro cross transfer station construction process won’t enough to guide a lot of large scale cross transfer subway stations construction in upcoming peak-time of metro construction, because of the difference of underground situation in different cities and the complexity of underground structures’ stress state.Based on the engineering background of the large scale cross transfer subway station at Chegongmiao in Shenzhen, the objective of this paper is to study the change of retaining structure and surrounding surface soil at subway station construction process by using theoretical method, large-scale finite element simulation method and engineering site monitoring method comprehensively. The main work of this paper will be shown as follow:(1) After referring papers, books and monitoring data, two two-dimensional finite element model was established to study retaining structure deformation mechanism and the propagation law of retaining structure’s deformation in soil at the process of subway station construction.(2) This paper collected 29 deep excavation engineering cases in Shenzhen and compared site monitoring data with finite element calculation data, then a simple and convenient formula about the surface subsidence around the excavation which can be used in Shenzhen was generated basing on the method that layer settlement law nearby a excavating foundation pit can be estimated by Rayleigh distribution function based on layer settlement monitoring data which was putted forward by Clough G W.(3) Setting sheltered reverse excavation method as a research example, the law that the variation of piles’ stiffness and support’s stiffness influence on staining structure’s deformation and surrounding soil’s deformation was studied by using a two-dimensional finite element model.(4) Using the dimension of the large scale cross transfer subway station at Chegongmiao in Shenzhen, a complex large scale three-dimensional finite element model was established to study the deformation result of surrounding soil and buildings, such as Chegongmiao subway station at 1st subway line and Fengshengting shopping street. After that, the change law of water surface elevation around subway station foundation pit at the process of construction was studied when using the construction method that excavation and precipitation are executed at the same time.(5) Collecting and organizing a large number of monitoring data of the large scale cross transfer subway station at Chegongmiao in Shenzhen, and then selecting some representative monitoring points’ data to compare with finite element calculation result for verifying the feasibility of the finite element method in this paper.