Modeling of the Bearing Capacity Degradation of Tunnel Invert Structures under Corrosion-Fatigue Coupling Effects

Le résumé fourni par la source

In salt-rich environments, tunnel inverts are subjected to the combined effects of corrosion and fatigue loads.Fatigue loads accelerate the transport of corrosion ions and the degradation of the bearing capacity of inverts.To elucidate the attenuation behavior of the bearing capacity of tunnel inverts in corrosive strata, this study proposed a method to calculate the bearing capacity of reinforced concrete eccentric components under fatigue loads.First, a set of coupled transport equations for sulfate and chloride ions was established in accordance with ion transport theory.Second, fatigue load parameters were incorporated into the diffusion coefficient equation, and the diffusion coefficient function was adjusted for fatigue.Finally, the degradation of the macroscopic mechanical properties of the components caused by corrosion was characterized, and a calculation model for the bearing capacity of a tunnel invert under corrosion-fatigue conditions was developed.Furthermore, the influence of fatigue load parameters on the degradation of the bearing capacity of the invert was studied.Results demonstrate that the degradation of the bearing capacity of the invert under fatigue load is positively correlated with the loading frequency and stress level.Bearing capacity decay accelerates with the increase in loading frequency and stress level.However, when the stress level is below 0.3, the effect of fatigue on the corrosion decay of the bearing capacity of the invert is not substantial.This study establishes a direct relationship among fatigue, corrosion, and degradation of the macroscopic bearing capacity of the invert.The proposed method provides a novel method to evaluate the durability of tunnels in complex environments.

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