Experimental study on the mechanical response of metro shield tunnels obliquely crossing ground fissures

• Published in: Tunnelling and underground space technology Vol. 132; p. 104849
• Main Authors: Gou, Yuxuan, Huang, Qiangbing, Kang, Xiaosen, Wang, Lixin, Yang, Xiaoqiang, Teng, Hongquan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2023
• Subjects: Failure mode; Ground fissure; Mechanical response; Metro shield tunnel; Model test; Numerical simulation; Failure mode; Numerical simulation; Model test; Mechanical response; Ground fissure; Metro shield tunnel
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2022.104849

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•The failure mode of the metro shield tunnel crossing the ground fissure obliquely is revealed.•The influence of ground fissure dislocation on structural mechanical response is studied.•The deformation of shield tunnel and segment induced by ground fissure dislocation are analyzed respectively.•The damage position and affected range of shield tunnel under the action of ground fissure are discovered.
Whether the shield tunnel can be adopted to cross the ground fissure is an important issue in the field of metro construction in Xi'an, China. To study this issue, the model test and numerical simulation on a metro shield tunnel that obliquely crosses a ground fissure were carried out. The lining internal force, segment deformation and failure characteristics under the action of ground fissure dislocation were investigated. The results show that the shield tunnel obliquely crossing ground fissure exhibits three-dimensional deformation of axial bending, horizontal local torsion, and axial tension–compression, if the ground fissure dislocation takes place. The segments near ground fissure present uneven vertical dislocation, horizontal slight deflection, and axial tilt. The lining is in bias pressure state, and cracks around segment bolts nearby the vault and inverted arch of shield tunnel when the actual ground fissure dislocation reaches 24 cm. The deformation and failure of shield tunnel obliquely intersecting with the ground fissure is in the torsional-shear mode, which affects the 8 rings in the hanging wall and the 5 rings in the footwall respectively, and these segments need to be strengthened. Also, some countermeasures and suggestions are proposed to deal with the adverse impacts of ground fissure on metro shield tunnel.