ABSTRACT
Monitoring of tunnels has evolved beyond simple displacement monitoring at a limited number of locations in the tunnel. A multitude of sensor types is available nowadays, making it possible to monitor displacements and deformations as well as material degradation related processes continuously. Automated, online, data collection makes monitoring not only more available, but also allows for continuous monitoring of tunnel locations where in-person access difficult or impossible. The result is a rising number of monitoring applications, not only for construction safety and control or purely for research purposes, but also the long-term use in tunnel operational control and structural health assessment. The increased monitoring offers exciting possibilities in tunnel engineering, but also increases the need to define clearly the needs and purposes of the monitoring solutions before sensor installation.
