ABSTRACT
This paper proposes a quantitative approach for selecting effective maintenance decisions for metro tunnels in order to reduce maintenance cost and ensure tunnel safety in the presence of structural degradation during the service life. A non-stationary gamma process is used to simulate the tunnel degradation and to investigate the effects of different maintenance measures on the life-cycle maintenance cost of metro tunnels in soft soil. Two commonly applied reinforcement methods, Aramid Fiber Reinforced Polymer and bonded steel plate reinforcement, are investigated in this study. The feasibility of the proposed methodology is demonstrated with maintenance decisions based on periodic and aperiodic inspection policies. Numerical results show that the optimization of maintenance decision can reduce the life-cycle maintenance cost of metro tunnels in soft soil while ensuring sufficient level of structural safety, and the maintenance decision with aperiodic inspection policy produces lower maintenance cost.
