Research On The Influence On Adjacent Existing Tunnel By Foundation Excavation Construction

With the continuous development of urban construction,the city land is also more and more tension,the construction of close proximity to the construction of the design has become an inevitable trend of development.Excavation of deep foundation pit in city will affect the adjacent tunnel obviously.This paper relies on the Chongqing Jiangbeicheng Tunnel Project and Chongqing rural commercial bank building.In this paper,the influence of excavation on the tunnel is analyzed,and the calculation results are provided for the similar projects in the future.The following problems are analyzed:(1)In view of the problem of foundation pit and tunnel,the mechanical model of the tunnel under the foundation pit and the mechanism of the failure of tunnel are introduced.Also,the paper introduces the working principle of the initial support and the tunnel lining of the tunnel.(2)ANSYS software is used to simulate the horizontal spacing of foundation pit and tunnel,a total of 12 cases were analyzed,and the relationship between the level of the tunnel and the tunnel two was obtained.(3)In this paper,the ANSYS software is used to simulate the foundation pit and the excavation process.At the same time,the change of tunnel in the construction process of the upper structure of the foundation pit is simulated.According to the calculation results,the tunnel displacement and stress state in the process of the foundation pit excavation and the stress state of the tunnel are analyzed.With the increase of the depth of excavation,the deformation of the tunnel is gradually increasing.(4)The LS-DYNA software is used t to simulate the influence of blasting excavation on the tunnel,the maximum vibration velocity and stress of the tunnel under the action of blasting load are analyzed.According to the calculation results,the maximum value of vibration velocity in the tunnel is less than that of the standard.which is 10cm/s,and the stress state of the tunnel is in the safe range.The influence of the excavation on the tunnel is in accordance with the requirements of the tunnel.(5)Depending on project monitoring data,comparing the measured data with the finite element simulation results,the finite element simulation results and the measured data show that the trend of the simulation is consistent,and the feasibility of the finite element simulation is verified.