Study On The Effect Of Deep Pit Excavation On The Adjacent S1 Line Base Of Wenzhou Rail Transit

Urban economic development is increasingly inseparable from the development of urban underground space,more and more deep foundation pit projects.Deep foundation pit excavation is easy to affect the stability of adjacent buildings(structures),resulting in engineering accidents,which will threaten the safety of people’s lives and properties.The deformation control of urban rail transit structure and foundation is very strict in operation,so it is of great significance to study the influence of deep excavation on adjacent rail transit.Based on the background of the foundation pit project of the underground garage of the road in front of the west square station of South EMU station in Wenzhou City,this paper analyzes the influence of the excavation of deep foundation pit on the S1 line foundation through the field monitoring and three-dimensional numerical simulation of the S1 line foundation near the deep foundation pit project,and puts forward some targeted prevention and control measures.The main research contents and conclusions are as follows:(1)Based on MIDAS / GTS platform,the field monitoring data of foundation pit are simulation,and a three-dimensional finite element analysis model of foundation pit excavation is established to simulate the construction process of foundation pit,the influence range of foundation pit excavation is analyzed,and the stress and deformation law of S1 railway subgrade with the excavation depth is discussed.(2)By analyzing the field monitoring data of vertical displacement and horizontal displacement of the Slope Toe and shoulder near the S1 line during the excavation of the deep foundation pit of the underground garage,the results of the settlement and large displacement of the slope toe and shoulder caused by the excavation of the foundation pit are obtained,the main reason is that there is no pipe pile at the base of S1 line,so the construction of foundation pit and excavation of foundation pit have great influence on the base of subgrade.(3)Based on the field measurement and numerical analysis,some measures to reduce the influence of deep foundation pit excavation on adjacent track subgrade are put forward,including the selection of reasonable support system and enclosure structure,necessary reinforcement measures and scientific excavation methods.In short,on the basis of the deep foundation pit engineering,through field monitoring and numerical simulation analysis,the influence regularity of the foundation pit excavation on the adjacent city railway line S1 is discussed,it is of practical value and practical significance to provide reference for the design and construction of similar deep foundation pit in the future.