Study On The Stability And Deformation Characteristics Of Foundation Pit In Subway Station

Along with the reform and opening up, China’s urbanization gradually accelerated and an influx of immigrants swarmed into the city. At the same time, the traffic pressure is increased and the subway travel gradually become one of the major travel choice in the city.The subway construction, especially on the building of the old city, will has a great impact on surrounding buildings to foundation pit. It is the content of this paper to explore the influence of the deep foundation pit excavation on the foundation pit and the surrounding environment, to analysis the influence on the surrounding environment and the supporting structure of foundation pit by construction, so as to ensure the safety of foundation pit and reduce the influence on the surrounding environment.This paper took Tianjin subway Line 1 east extension project of shuangqiaohe subway station as the project and study on the stability and deformation of subway station foundation pit.(1)The thesis introduces the elaboration of deep foundation pit support design,common supporting structure type and scope of application, the stability of the deep foundation pit and deformation theory basing on the stability of the foundation pit, deformation and finite element both at home and abroad research status.(2)The foundation pit of shuangqiaohe subway station adopts underground continuous wall and the inner support support scheme by Lizheng deep foundation pit supporting software 7.0.In this paper, the overall stability of foundation pit, stability against overturning stability and uplift stability were checked and analyzed the rules of internal force and displacement variation law.(3)This paper simulates the foundation pit by numerical simulation software MIDAS/GTS/NX and analyze the surface settlement, the horizontal displacement of the wall and the rule of the basement uplift caused by the excavation of the foundation pit.The simulation results were compared with the actual monitoring and the results showed that the two are more consistent and the simulation value of ground subsidence is smaller than the actual monitoring value.In this paper, the main reason of the difference of soil settlement caused by the precipitation of the actual project is analyzed.(4)Comparing the effect of the basement section reinforcement on the basement uplift and the lateral displacement of the underground diaphragm wall, the results show that the basement reinforcement can improve the lateral displacement of the basement uplift and the lateral displacement of the underground diaphragm wall. At the same time,the thesis analyzes the improvement of the force concentration in the foundation pit supporting structure with internal support.