Structural behavior degradation of corroded metro tunnel lining segment

Abstract

The static loading experiment of eight corroded full-scale specimens and the finite element simulation were carried out to study the structural behavior degradation of the metro lining segment under different corrosion conditions and loading eccentricities. The results indicated that the severe corrosion of the intrados tensile rebars and large loading eccentricity were the two primary factors of the structural behavior degradation of the segment. The bearing capacity and bending stiffness of the segment were not affected by the corrosion location, while they decreased with the increasing corrosion degree and loading eccentricity. The decreased loading eccentricity reduced the ductility of the corroded lining segment and resulted in a higher possibility of small eccentric compression failure. With the increased loading eccentricity, the corrosion degree had a more obvious impact on the structural behavior of the corroded segment, especially when loading eccentricity exceeded the critical value of 0.20 m. Therefore, it is necessary to avoid excessive local lateral water and soil pressure, control the effect of tunneling construction of new tunnels when approaching the aging tunnel, and prevent the premature corrosion of rebars in segments subjected to the attacks from aggressive agents.