Characteristics and treatment measures of lining damage: A case study on a mountain tunnel

Abstract Lining damage is a crucial issue affecting the operation mountain tunnels, as it diminishes the bearing capacity and shortens the service life of tunnels. Investigation and treatment of lining damage are essential for enhancing the safety and prolonging the service life of tunnels. This paper presents a case study on the characteristics and treatment measures of the lining damage of a mountain tunnel by field investigation, numerical simulation and in-situ monitoring. To better understand the operational status of the tunnel structures subject to lining damage, water leakages, cracks and voids behind the lining are detected to obtain the distribution and morphological characteristics of lining damage. Detection results show that voids behind the lining are the main cause of lining cracking, and thus, the mechanical performance and failure mechanism of lining structures with voids are evaluated by numerical simulation. Based on the results, treatment measures of lining damage are adopted, including crack grouting, shotcrete support, and reconstruction of the secondary lining. Finally, the effectiveness of treatment measures is investigated by analyzing field monitoring data. Lessons learned from this case study are discussed, thus providing a reference for the treatment of lining damage in other tunnels.