Research On The Influence Of Pile Foundation Construction Of Jinzhong River Bridge On Existing Adjacent Subway Tunnels

With the development of urbanization in China,the city scale is getting larger and larger,the city population is getting larger and larger,and the urban traffic pressure is getting larger and larger.In order to relieve the traffic pressure of the city and save the land,the development and utilization of the urban space has developed from the original plane space to the three-dimensional underground,ground and air space,the development of underground space of urban traffic is mainly Metro,the development of ground is mainly urban road,and the development of air is mainly bridge construction.However,in the process of three-dimensional traffic development,the structures of different dimensions inevitably intersect,especially the bridge and the adjacent subway tunnel.The construction of the bridge pile foundation near the completed subway tunnel will inevitably have an impact on the original subway tunnel.In serious cases,it will cause damage to the original subway tunnel and cause the loss of public property,put People’s lives at risk.Therefore,it is very necessary to study the influence of bridge pile foundation construction on existing adjacent subway tunnel.Based on the construction project of Jinzhong River bridge,through the comparison of bridge schemes,theoretical analysis,numerical simulation and on-site monitoring,in this paper,the influence of pile foundation construction and operation on the tunnel structure of the existing adjacent Metro Rail Transit Line 2 is studied:(1)the feasibility of the bridge scheme is determined in accordance with the relevant design regulations,construction codes and regulations,and in combination with the topographic and geomorphological conditions and hydrogeological conditions of the construction site,and then the design of the upper and lower structures of the bridge is carried out,the concrete construction scheme is also considered.(2)the load transfer mechanism,load effect and tunnel deformation theory of pile foundation are analyzed.(3)according to the design and construction drawing,construction method,construction sequence,geological and hydrological conditions of the project site and the actual site conditions of the tunnel structure of the existing Rail Transit Line 2,etc.three-dimensional finite element model is established for numerical calculation and analysis.Seven typical working conditions were selected for numerical simulation analysis.(4)the section points of the tunnel structure calculated by numerical simulation are consistent with the site monitoring points,and the working conditions corresponding to the actual monitoring data are also corresponding to the working conditions calculated by numerical simulation.The cause of formation of the site monitoring data is analyzed,the results are compared with those of numerical simulation,and the reasons for the difference between them are analyzed.Through the comparison and analysis of the numerical simulation and the actual monitoring data,it is found that the calculated values of the numerical simulation of the settlement of the tunnel structure are basically in agreement with the comparison curves of the actual monitoring values,the feasibility and validity of the model are verified by practice,which provides a reference project for the similar projects to be built in this area.