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

In recent years,with the construction of a large number of subway projects,the deep foundation pit project has been rapidly developed.Because of its special location,subway foundation pits have more stringent requirements in controlling their deformation and their impact on the surrounding environment.This paper takes the deep excavation engineering of Xuzhou subway station as the engineering background,adopts the methods of theoretical design,on-site monitoring and numerical simulation to study the deformation law of foundation pit during excavation and support,and the factors affecting the stability of the foundation pit are studied.Firstly,combining with the engineering practice and the selection of supporting structures for foundation pits,the appropriate supporting structure is selected and checked with Lizheng 7.0,which proves that the deformation,stress and stability of the supporting structures during the foundation pit construction are meet the requirements of the specification.Secondly,the paper focuses on FLAC3 D software to simulate the excavation and support construction process of the foundation pit model,and the law of lateral movement of the retaining structure,wall top displacement,settlement deformation,axial force change and settlement of surrounding buildings are discussed.Then through on-site monitoring of the project,the field measurement results are compared with the simulation results.The results show that although the simulated values are slightly smaller than the monitored values,the overall deformation trend is consistent,which can reflect the actual deformation characteristics of deep excavation.It shows that the numerical simulation has a predictive and guiding role in the excavation process of the foundation pit and is very beneficial to the information construction of the foundation pit project.Finally,because of the large number of factors affecting the stability of the foundation pit,numerical simulations are used to study the influence of the stiffness of the diaphragm wall,the depth of the diaphragm wall,the number of support layers,the stiffness of the support,the soil parameters,etc.on the stability of the foundation pit.The research results can provide reference for similar projects in design and construction.