A Numerical Case Study of Soil-Pile-Shield Tunneling Interaction for Guangzhou Subway Project

A three-dimensional finite-element analysis was performed to analyze the interaction between pile and ground due to tunnel excavation in Guangzhou No. 2/8 extension Subway project. The 3D FE mesh includes 50 original piles and 80 underpinned piles surrounding the tunnel excavation. Three different tunneling scenarios were simulated, from which the ground settlement curves as affected by the surrounding pile groups were studied. The FE analysis further demonstrates that simultaneous two tunnels excavation (keeping abreast) is the worst scenario for the ground settlement and for the consequent effects on the superstructure. The separate 2-D FEM analysis shows that the piles can easily be subjected to negative skin friction and excessive bending during the shield tunnel excavation going through the piles. These additional bending and negative skin friction should be carefully considered during design and construction stages.