Modelling the impact of deterioration on the long-term performance of Dublin Tunnel

The influence of tunnel deteriorations on its long-term performance has received extensive attention recently. Most studies considered deteriorations by manually varying the magnitude of parameters like permeability and stiffness, neglecting their time-dependent variation. This paper addresses this gap by investigating the impact of time-dependent deteriorations on the long-term behaviour of the aging Dublin Port Tunnel (DPT). A modified analytical relative ground-lining permeability model and calculated deteriorated permeability for DPT were presented, with steps and procedures generalised. The deteriorated permeability was incorporated into the hydraulic deterioration model, together with mechanical deterioration, offering a more holistic and realistic prediction of DPT’s long-term performance than previously available. Numerical results, compared against field measurements, showed (1) assuming constant permeability fails to accurately capture time-dependent liner deformation, and hydraulic deterioration is the dominant factor inducing an approaching squatting deformation mode; (2) continuous mechanical deterioration leads to a linear growth in vertical and horizontal convergence over time, with vertical convergence being more pronounced, indicating a squatting contraction deformation mode; (3) the comparison quantitatively evaluates the impact of individual and coupled hydro-mechanical deterioration on DPT’s long-term behaviour and the agreement between field data and numerical results confirms coupled lining deterioration is the root cause behind the observation.