Analysis of the Impact of Shield Tunneling Under Existing Subway Station

Abstract

To ensure the safety of existing subway station structures and the normal operation of the metro, this study focuses on a specific engineering case in Suzhou’s metro, where shield tunnels were initiated at a close distance to pass beneath an existing subway station. Numerical simulation method was employed to analysis the impact of shield tunneling parameters on the deformation of the existing station structure under conditions with and without pre-reinforcement boundaries. Additionally, the study involved a comparison with monitoring data to validate the reliability of the numerical simulation approach. The results indicate that: 1) Controlling the shield tunneling parameters, such as setting appropriate shield tunneling face support force and tail grouting pressure, is beneficial in managing the deformation of the existing station; 2) The elastic modulus of an equivalent grouting layer has the greatest impact on settlement. Choosing the appropriate grouting material during construction is a key approach to control settlement. 3) Strengthening the soil strength in the reinforcement area and increasing the thickness of the track slab have a minimal impact on the settlement of the track slab at the existing station. However, the former is beneficial for the stability of the shield excavation face. The latter enhances the existing structure’s resistance to deformation.