Analysis of the Influence of Adjacent New Pile Foundation Construction on the Structural Deformation of the In-service Subway Tunnels

Abstract Taking the construction project of a new bridge pile foundation above an in-service subway in Xi’an as an example, considering the influence of horizontal symmetrical construction of pile foundation hole forming on the deformation of different sections of asymmetric tunnels, a three-dimensional finite element geometric model of pile-tunnel-soil is established based on ABAQUS software. Through the numerical simulation analysis of the structural deformation behavior of the in-service subway tunnel under the two construction stages of pile foundation hole forming and concrete pouring, the horizontal and vertical deformation laws of the key points of the in-service subway tunnel caused by the construction of the adjacent new pile foundation are analyzed from different angles.The calculation results show that: the deformation of the interval tunnel is mainly caused by vertical displacement, resulting in overall settlement of the tunnel. However, the settlement value is within a controllable range and does not affect the normal operation of the in-service subway tunnel. The concrete pouring stage has a greater impact on subway tunnels. The research work has important reference value for the reasonable safety monitoring and control of similar construction projects.