Cracks analysis of highway tunnel lining in flooded loess

Abstract

Lining cracking is one of the common problems in highway tunnels constructed in regions where loess is present. In this paper, the finite-element method was used to investigate the deformation and mechanical properties of a tunnel lining in different flooded conditions. The Duncan–Chang E–B model was used to simulate the stress–strain behaviour of loess, which was verified by numerical simulation of the triaxial tests. The simulation results were compared with the field monitoring data collected from the Xinzhuangling loess tunnel. The results show that finite-element calculation of the Duncan–Chang E–B model developed in Ansys simulation software is reliable. Tunnel lining cracking is caused by the flooded surrounding rock. The vault cracks prior to the sidewall and more seriously than the sidewall. After the foundation is flooded, the tensile stress of the vault decreases, but the compressive stress of the sidewall significantly increases. Flooded mountain cracks cause a greater damage effect to the tunnel lining than a flooded foundation. The reason for cracking and the process of development of lining cracking in a loess tunnel are also further discussed.