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[Display omitted] • The failure mode of metro tunnel crossing the edge of land subsidence area is revealed. • The influence of land subsidence on the structural mechanical response are studied. • The damage position and affected range of metro tunnel under the influence of land subsidence are discovered. • The countermeasures are discussed according to different affected positions. Land subsidence is a prominent engineering geological problem faced by many cities in the world and poses a serious threat to urban infrastructures. Xi'an is one of the cities in China that has suffered the most serious land subsidence disasters and has thus faced the challenges in its ongoing metro construction. To solve this problem, in this paper we carried out a model test and numerical simulation of metro tunnel that crosses a land subsidence area and analyzed the mechanical response of the tunnel and the deformation and failure characteristics of the lining. The results show that the tunnel exhibits downward flexural deformation in the middle, slight warpage on both ends in the longitudinal direction, and local torsion in the horizontal direction in the presence of land subsidence, the maximum deformation of the ground surface is about 80% of the tunnel deformation. Furthermore, the vault and inverted arch are in opposite tension–compression states, and the lining stress decreases inside the subsidence area but increases outside it. When the actual subsidence reaches 225 cm, the metro tunnel crossing the edge of the land subsidence area has failed. We find that the deformation and failure of metro tunnel crossing land subsidence area is a combination mode of flexural tension–compression and local torsion, which affects 2.5 times the length of the intersection between the tunnel and the subsidence area. Also, some countermeasures and suggestions are proposed to deal with the adverse impacts of land subsidence on metro tunnels. [ABSTRACT FROM AUTHOR]

[Display omitted] • 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. [ABSTRACT FROM AUTHOR]