Engineering Monitoring And Finite Element Simulation Analysis Of Deformation Characteristics Of Deep Foundation Pit In Subway Station

With the continuous acceleration of urbanization in China,the potential contradicti on between the increasing urban population and the limited urban land area is increasing ly exposed,which has become one of the main factors restricting the planning and devel opment of large and medium-sized cities.In order to alleviate this tension,rail transit en gineering has been widely used as the main way to develop and utilize underground spa ce.Although the subway era has been prevalent,many engineering problems are still ha rd to avoid.As the construction of subway stations is mostly located in the regional cent er of bustling downtown,it means that the narrow construction space,complex surround ing environment,reasonable design scheme and construction operation will affect the st ability and safety of the foundation pit.However,faced with the increasing scale of foundation pit and the increasingly co mplex construction environment,it requires us to control the design of foundation pit de formation,neither too conservative to cause economic waste,nor too risky to advance.Therefore,in order to better control the deformation of the foundation pit,save the proje ct cost and facilitate the construction,we need to master the deformation law of the foun dation pit excavation in detail,and at the same time,we need to advance towards the res earch direction of reasonable change of design parameters.Based on the deep foundatio n pit project of a subway station in Hangzhou,this paper compared and analyzed the res ults of field monitoring and simulation calculation to explore the rule and mechanism of foundation pit excavation deformation,and explored the influence of supporting design parameters on foundation pit deformation by changing some simulation design paramet ers.The main contents are as follows:(1)Read relevant literature,and sort out the application process and research status of engineering monitoring and finite element simulation in deep foundation pit engineering.This paper expounded the engineering characteristics,deformation types,supporting types that include their respective applicable scopes of deep foundation pit in detail,as well as the stress mechanism of supporting structure and the checking calculation of foundation pit stability.(2)Based on the field the field measured data,the soil settlement around the foundation pit and the horizontal and vertical displacement and deformation rules of the retaining structure are summarized.And it is verified that the space effect exists in the whole process of excavation.(3)The finite element simulation software(MIDAS/GTSNX)is introduced.Based on this software,the whole dynamic excavation process of the foundation pit is analyzed,and the numerical calculation results are compared with the measured results to obtain a relatively consistent deformation curve,which proves that the finite element software has the application value of guiding the actual excavation of the project.(4)By changing the design parameters of the simulated structure,such as the thickness and depth of the diaphragm wall,the stiffness of the inner support and the spacing of the horizontal inner support,it is concluded that the increase of the stiffness and the embedded depth of the enclosure wall and the stiffness of the inner support within a certain range can reduce the deformation of the foundation pit,and through the different levels within the span layout scheme and simulation comparis on analysis between the original design,synthetically to verify the original design can s atisfy the actual excavation engineering of safety,economical and practical,providing a certain reference value for similar projects.