Analysis of Ground Movements in Shield Tunneling and Their Effects on Adjacent Bridge Pile Foundations.

The movement of the ground and the redistribution of stress caused by shield tunneling result in deformations and changes in internal forces in bridge pile foundations, which, in turn, affect the safety of pile superstructure. A numerical computational model based on the modified Mohr–Coulomb (MMC) criterion was proposed to analyze the effects of shield tunneling on the stability of the pile foundations of existing bridges during the early, middle, and late stages of shield tunnel construction. A 3D numerical model of the shield tunnel and bridge pile foundation was constructed using the finite element software Midas GTSNX. The ground movements and deformation patterns of pile foundations were analyzed throughout the entire shield tunneling process beneath existing bridge pile foundations. Results demonstrate that utilizing the elastic-plastic constitutive model founded on the MMC criterion is more effective for illustrating the surface settlement pattern induced by shield tunnel construction. Bridge piles are continuously deforming during the construction of a shield tunnel. The deformation of a bridge pile is maximized when a shield tunnel reaches the foundation of the pile. The deformation of bridge pile foundations remains stable after passage. The deformation and bending moments of bridge pile foundations decrease with an increase in distance from the tunnel. The influence on bridge pile foundations is reduced with an increase in distance from the shield tunnel. This study provides a good reference for the construction quality control and safety assessment of similar tunnel projects. [ABSTRACT FROM AUTHOR]