Finite Element Analysis (ANSYS) Of Harbin Subway Station Excavation And Field Monitoring Research

With the development of the city,the road construction is complex,and the urban ground space becomes smaller and smaller.With the rapid increase of population and the number of vehicles in the city,the pressure of public traffic is increasing,the traffic on the road is very crowded,and people travel slowly.In order to further develop the city and reduce the traffic pressure,the subway has become an inevitable choice for the construction of a modern city.The construction of urban subway is close to the surrounding high-rise buildings and underground pipelines,coupled with the complex nature of the underground soil and stratigraphic variation,the excavation of the foundation pit is very difficult,and the safety of the foundation pit construction is paid great attention to.This paper briefly introdu ces the present situation of the development of the subway in China and abroad,and the main characteristics of the foundation pit engineer ing,and introduces in detail the theoretical basis,design calculation method,the deformation characteristics of the foundation pit and its deformation mechanism.In addition,according to the geological conditions,hydrological conditions,supporting structure and surrounding environment characteristics of Harbin Metro Line 3 second-phase project of Xiangjiang Road Station,design and construction monitoring program,including the layout of monitoring points,monitoring contents,monitoring method and frequency etc..Combined with the deep foundation pit of Xiangjiang Road Station of Harbin Metro Line 3,the Ansys finite element method is used to simulate the excavation and supporting process of the foundation pit.According to the characteristics of Xiangjiang Road`s foundation pit,it`s simplified as a two-dimensional plane problem.Considering the soil and retaining structure is discontinuity,contact elements is used in Ansys model,and Drucker Prager ideal elastic-plastic constitutive soil model is used.The "death element" function in Ansys is used to simulate excavation process with nonlinear analysis in several construction condition.Then simulation results and measured data is compared,and the reason for difference of them is analyzed.The comparison results show that the finite element results of deformation of retaining structrue and steel support axial force fits the mearuement results,so the Ansys finite element method for foundation pit which is simplified as a two-dimensional problem analysis is reliable.