Abstract: Reliability of the electromechanical system used in a tunnel is crucial for the safety operation of the tunnel. The reasonable selection of the maintenance strategy from the perspective of cost and performance control is an important issue for operation and maintenance practice. To solve the programmed problems existing in the current research on equipment maintenance strategy, a maintenance strategy dynamic selection model (MSDSM) is proposed. The model is based on the prediction of the equipment reliability trend under the premise that the equipment integrity rate meets the standard and by considering the longterm maintenance cost and social cost of equipment operation and maintenance. The laws of the maintenance strategy selection under different situations are analyzed using the MSDSM by considering the example of a drainage pump based on the historical data of the electromechanical equipment in Dalian road tunnel. The results show the following: (1) Adopting the preventive maintenance strategy during the whole life cycle of the equipment is helpful for reducing the maintenance cost of the equipment.(2) According to the effect of preventive maintenance, the preventive maintenance strategy should be adopted in the early life of the equipment, and preventive replacement strategy should be adopted in the later life of the equipment.

Key words: tunnel electromechanical equipment, longterm performance, maintenance strategy, dynamic selection, comprehensive cost