Research On The Deformation Monitoring And Numerical Simulation Of Deep Foundation Pit In Hangzhou Metro Station

With the sustained and rapid development of China's economy,the population of medium and large cities is increasing year by year,and urban traffic congestion gradually emerges,with increasing load,which restricts the planning and development of urban traffic.In order to solve this problem,facilitate people to travel,improve the operation rate of the city,and alleviate traffic pressure at the same time,medium and large cities choose to build and plan subway lines,and further develop and utilize underground space.The vigorous development of subway construction at the same time also brought a lot of engineering problems,because most of the subway station in the city center area,narrow construction site and the surrounding environment is complex,deep foundation pit excavation depth,excavation construction will produce deformation,leading to instability,the ground settlement around the foundation pit,building tilt and a series of problems,directly affect the safety of foundation pit and surrounding buildings.Therefore,it is of great value and significance to study the deep foundation pit engineering of subway station and analyze the deformation law of deep foundation pit excavation.Based on the deep foundation pit project of Hangzhou Subway Wulin Square station,this paper studies and analyzes the deformation law and mechanism of deep foundation pit excavation by means of field monitoring and comparison with numerical simulation results,so as to provide certain reference for practical projects.The main research contents of this paper include the following aspects:(1)Read literature and data to understand the research status and development prospect of deep foundation pit excavation deformation and finite element software application at home and abroad.This paper summarizes and analyzes the characteristics of existing deep foundation pit projects at home and abroad,including foundation pit excavation and support methods,and focuses on the study of surface settlement,deep foundation pit enclosure structure,deformation mechanism of foundation pit bottom uplifting deformation law,control methods to reduce deep foundation pit deformation,and related factors affecting foundation pit deformation.(2)Based on the analysis of subway site monitoring data,the horizontal and vertical displacements of the foundation pit envelope under different excavation conditions,as well as the deformation laws caused by the ground settlement around the foundation pit and the soil displacement outside the foundation pit are analyzed.(3)In combination with the practical situation of construction excavation,etc,analysis of engineering geology,the types of retaining structure,and using the finite element software Midas GTS NX 3 d modeling,numerical analysis,for the convenience of calculation and analysis,the model is simplified properly,to determine the model size,material selection and parameters are modified Mohr coulomb constitutive model calculation in the process of construction condition is determined.The simulation resultsunder the key construction conditions are compared with the actual monitoring data,and the reasonable reliability of the model is determined.It is proved that the numerical simulation analysis through the finite element software has a good guiding role in the actual project.