Study On Deformation Of Metro Station Envelope And Surrounding Buildings

With the further development of urbanization,Subway construction is springing up in every major city in China.The unreasonable excavation of open-pit subway stations will break the stress balance of the surrounding soil,which will cause the instability of foundation and damage to the adjacent buildings.In this paper,taking the open-cut station project of railway subway station of Dalian Metro Line 5 as the background,applying the research method combining the measured data analysis and numerical simulation to analyze the deformation and change characteristics of open-cut metro station,such as horizontal displacement,supporting axial force,surrounding surface and building settlement.The main research results are as follows:(1)The horizontal deformation curve of pile is similar to the cantilever beam in the initial stage of foundation pit excavation,and the overall performance is toppling phenomenon.The deformation curve shows a parabolic shape as the excavation depth increases,and the maximum deformation point shows a downward trend as the excavation depth increases.Among them,the maximum horizontal displacement of pile is 8.3mm,which is about 0.35‰ of the excavation depth of the foundation pit,with an average of about0.31‰.(2)The axial forces from the foundation pit excavation to the main construction process of the station generally show an expanding trend but are in a safe and stable state.In the early stage of support erection,the axial force increases rapidly,and then slows down.After the removal of the lower support,the axial force of the upper support increases slightly,but soon becomes stable.(3)The surface section settlement curve shows a small state at both ends of the middle section.The maximum settlement position has an epitaxial phenomenon as the excavation depth of the foundation pit increases.During the construction process of the station,the maximum settlement occurs at a position of about 9 m from the edge of the foundation pit.The maximum surface settlement value is about 0.36‰ of the excavation depth of the foundation pit,and the average value is about 0.34‰,which is about 1.03 times of the maximum horizontal displacement of the pile,and about 1.0 times of the average value.(4)The deformation curve of the building is basically consistent with the surface settlement curve.The maximum settlement occurs at the position of 9 m ～ 12 m from the edge of the foundation pit,while the settlement is extremely small,about 1mm,at the position of50 m from the edge of the foundation pit.