Framework for maintenance management of shield tunnel using structural performance and life cycle cost as indicators

In the past decades, many shield tunnels have been constructed for use in important lifeline infrastructure such as roads, railways, water supply systems and sewers. A good performance of the tunnel requires appropriate maintenance associated with a substantial cost; therefore, a rational maintenance approach is required. Preventive maintenance has been previously applied in an efficient and effective manner. However, the evaluation of structural performance, as well as the choosing an appropriate maintenance management strategy, is still a challenge. This paper proposes a maintenance framework for the shield tunnel. Structural performance and life cycle cost are evaluated as the major indicators accounting for the major deterioration (e.g. steel corrosion, cracking, etc.). The structural performance-based strength cost for an expected service time is used as the criterion to select a rational maintenance plan. Furthermore, structural reliability analysis is performed to validate the proposed framework and investigate the influence of deterioration model. The proposed framework was successfully applied to the maintenance of a trunk sewerage pipe for choosing a rational maintenance plan.