State-of-the-Art of the Tunnel Maintenance in Taiwan and Challenges to Sustainable Development

Tunnel construction of Taiwan started early in late nineteenth century. Within 125 years, tunnel maintenance in Taiwan went through several stages. In early days, engineers meant tunnel excavation. Tunnel inspections, repairs and reinforcement were performed only when serious damage was observed. As the number of damaged tunnels increased, investigations of the most frequently recurring anomalies revealed that the degradation of tunnels in Taiwan was inevitable and usually occurred in an exceptionally shot period. Frequent earthquakes, a high ground water level and poorly cemented rock masses provides a severe environment for engineering structures. Hence, to adapt more effectively to the environment, tunnel maintenance started to consider the entire life cycle of a tunnel. Recently proposed monitoring technologies and anomaly cause diagnosis methods of Taiwan have been demonstrated to be useful in supporting the sustainable operation of tunnels.