3D numerical investigation on response of shield tunnel under combined effects of fire and structural loading

摘要

? 2022 Elsevier LtdAs a significant infrastructure hazard, fires in tunnels have brought about a great deal of economic and social losses each year. From a holistic tunneling design perspective, it is essential to predict accurately the displacements and internal forces of the lining under coupled effects of elevated temperatures and various loading conditions. To this end, an elaborate three-dimensional (3D) numerical model, which incorporated the concrete segments, reinforcing rebars and connecting bolts, was established to investigate the deformation and failure mechanism of the segmental ring in shield tunnels under coupled effects of fire and structural loading. The validation based on the experimental results of segment lining and joints shows that the established model can be employed to analyze the entire tunnel ring structures. Two types of numerical models, i.e., single-ring and three-ring models, were established and the thermo-mechanical coupled performance were examined. Based on the verified model, the general temperature field and deformation distribution were described and elaborated. With respect to the significant insights on mechanical behaviors of shield tunnel rings in fire, the results of inner force redistribution, the joint opening elaboration and the failure mechanism of the shield tunnel structure under fire effects and initial loadings were further discussed. The results of this study can provide valuable guidance for the fire resistance design in the tunnel.