AUTHOR=Wang Ning , Jiang Yalong , Geng Daxin , Huang Zhanjun , Ding Haibin 

TITLE=Numerical Investigation of the Combined Influence of Shield Tunneling and Pile Cutting on Underpinning Piles

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2022.896634

DOI=10.3389/feart.2022.896634

ISSN=2296-6463

ABSTRACT=In this paper, the combined influence of shield tunnelling and the old pile cutting process on underpinning piles is investigated through Finite Element Method (FEM) modelling based on a shield tunnel project in Nanchang Metro Line 2, China. Numerical models are developed to analyze the influence of intersection angles and the vertical distance between the underpinning foundation and tunnels on the mechanical responses of underpinning piles during tunnel excavation. Simulation results show that the bending moment of the underpinning piles decreases with increasing vertical distance between the pile and tunnel, and is in inverse proportion to the intersection angle between the underpinning beam and tunnel. In addition, the maximum pile bending moment occurs in the buried depth of the tunnel axis, indicating a high damage risk in this part. According to the simulation results, more attention should be paid to the underpinning piles in case that a small vertical distance and intersection angle is encountered.