Influence of Foundation Pit Excavation on Structural Safety of Adjacent Existing Tunnels

Abstract

The existing subway tunnel will be deformed due to the excavation unloading of the adjacent foundation pit, which will affect the normal use and safety performance of the tunnel. Therefore, it is particularly important to evaluate the impact of foundation pit engineering on the structural safety of adjacent subway tunnels. The third phase of Tianjin Yellow River Hospital, with a depth of more than 5m, is close to Tianjin Metro Line 2. The results show that the displacement of soil around foundation pit and subway tunnel segment increases with the excavation process, but is less affected by floor load. In addition, the vertical displacement of subway tunnel segment is mainly affected by foundation pit dewatering, its axial force and bending moment remain stable in the construction process, and the crack checking result is within the allowable range. The results of this paper can provide an effective reference for the project impact assessment.