Resilience analysis of tunnel lining under creep-induced convergence of soft rock: Characterization and field application

Abstract

Assessment of tunnel lining resilience is critical to ensure long-term structural stability under soft rock excavation. In this paper, a novel analytical approach is proposed to assess its performance, considering the time-dependent properties of tunnel deformation. Based on the complex stress behavior of lining, the ratio of compressive and tensile stress to its strength is selected as a performance indicator (Q) of resilience. A new resilience metric (Re) is defined to explore the non-uniform stress behavior of the lining. This metric is calculated as the ratio of the integral of disturbed Q to that of undisturbed Q by incorporating the spatial parameters of the lining. Subsequently, the rationality and applicability of the proposed method are validated through a case study involving a diversion tunnel exhibiting time-dependent deformation behavior. The parameters of compressible layer support are optimized based on Re. The results indicate that the lining Re decreases substantially (Re < 0.6) within three years and stabilizes at 0.34 after 50 years. The analysis of lining Q behavior reveals that the arch foot and invert experience more substantial reductions in Q during operation. The incorporation of compressible layers as support enhances the sustained resilience of the lining once a critical threshold is reached, maintaining Re at an approximately constant level over time. This improvement depends on the energy absorption capacity and utilization efficiency of compressible layers.