Study on the Multi-Factors Influence Characteristics of Tunnel Safety under Sulfate Attack

To investigate the multi-factor influence characteristics on the safety of tunnels subjected to sulfate attack, based on classical damage mechanics theory, the actual corrosion state of tunnel lining is considered as a combination of the uncorroded and fully corroded states. A numerical model is established to explore the effects of various factors on the safety of tunnels under sulfate attack and analyze their sensitivity. The results show that: (1) When tunnel lining is eroded by sulfates, the corrosion at the arch foot is more hazardous under the same conditions. (2) Increasing the initial strength and thickness of tunnel lining can improve the safety of tunnels before corrosion but have limited effects on improving safety after sulfate attack. (3) After corrosion occurs at a specific part of the tunnel lining, it mainly affects the safety of that corroded part while having minimal impact on the safety of other parts. (4) The sensitivity of various factors affecting the safety of tunnels under sulfate attack is in the following order: vertical load > initial lining thickness > initial lining strength > corrosion location > lateral stress coefficient > elastic resistance.