Influence Analysis On Adiacent Metro Tunnel In Progress Of Deep Foundation In Hangzhou Area

Recently,Hangzhou metro line is developing rapidly.But at the same time,the foundation pit excavation projects have become lager and lager which often has adverse effects on the adjacent tunnel structures.The excavation process of deep foundation pit often creates additional stress and deformation on the tunnel structure.Especially in Hangzhou soft soil area,this phenomenon may seriously affect the stability of tunnel structure and safety of subway operation.Therefore,it is of great engineering significance to predict reasonably the influence of foundation pit excavation on adjacent tunnels in Hangzhou area.Aiming at this problem,this paper uses the methods of mathematical statistics,field measurement and numerical simulation to study.The specific contents are as follows:1)Through collecting cases of foundation pit engineering close to metro tunnels in Hangzhou area,based on the analysis of geological conditions in Hangzhou,this paper have analyzed the factors including the excavation depth of foundation pit engineering,the relative distance between tunnel and foundation pit,space-time effect and construction conditions by using mathematical statistics method,and have summarized the basic rules of adjacent tunnels displacement caused by foundation pit excavation.2)Based on a typical engineering case in Hangzhou area,this paper has summarized the displacement rule of foundation pit adjacent to tunnels in progress of excavating.The content include:the distribution law of various displacements along the tunnel,the development law of the maximum displacement of tunnel along with the time,the relationship law between deep soil displacement and the tunnel displacement,the influence range of tunnel displacement caused by foundation pit excavating.3)By using the numerical simulation software Plaxis,this paper has established the foundation pit-soil-tunnel model to compare the different influence rule of various parameters such as the changes of foundation pit supporting system,soil and tunnel structure.The rule of tunnel structural deformation by deep excavating is concluded.