Decision method on optimal time of preventive maintenance for metro shield tunnels in soft soils

• Main Authors: Junhua Xiao, Jinrong Song, Dong Liang, Lihua Zhai, Xingzhong Nong
• Format: Article
• Language: English
• Published: Elsevier 2020-12-01
• Series: International Journal of Transportation Science and Technology
• Subjects: Metro shield tunnel; Prediction model; Optimal time of preventive maintenance; Cost-benefit analysis; Soft soils
• Online Access: http://www.sciencedirect.com/science/article/pii/S204604302030023X

A reasonable maintenance time is vital in the metro shield tunnel maintenance to keep good structural performance and reduce maintenance cost. Lacking predictability, the existing maintenance mode cannot effectively resolve the contradiction between the limited maintenance cost and the growing maintenance need in the future. In this study, the degradation model of metro shield tunnels in soft soils was studied to predict the long-term serviceability. Based on that, a method was proposed to decide the optimal time of preventive maintenance for metro shield tunnels. It was found that the tunnel decay process can be expressed by the inverse exponential function-based prediction model. The cost-benefit analysis method was adopted to determine the optimal preventive maintenance time, considering the maintenance time, the maintenance cost and the maintenance measures adopted. The flow chart of this method and an application example were presented. Results can help metro operation owners to develop more scientific and reasonable preventive maintenance plans for shield tunnels in soft soils.