Prediction for Long-Term Deformation of Existing Tunnels Induced by Underground Excavation in Shanghai Subway Project

Abstract

The long-term deformation behavior for existing underground structures induced by tunneling is a hot problem which engineers designing and practicing in urban subway engineering encounter more frequently than in the past. Based on the Shanghai Railway Transportation project, the long-term deformation of existing tunnels caused by underground excavation is proposed considering soil consolidation by 3D consolidation finite element numerical simulation method. The maximum consolidation deformation values for service Line 4 are obtained within the time span of thirty years after the tunneling excavation is completed. Furthermore, comparisons between numerical simulation results and the field data are conducted according to site investigations. It is concluded that the calculated consolidation displacements are in general consistent with the observed shapes and the soil consolidation has a significant influence on the deformation behavior of existing tunnels during the service process.