ABSTRACT
Management and maintenance of tunnels requires the application of high performance lining inspection techniques. Many infrastructure maintenance contracts, including those of tunnels, are managed through quality indicators. In order to assess these indicators, objective inspection tools and devices are necessary. This paper will present different automated techniques; some brand new, while others well-known like the Lidar technique. We will describe how the results obtained in different tunnels through visual inspections performed by specialized surveyors, can be completed with the information obtained from a combination of techniques, mainly based on imaging and laser. The automated inspection offers a better knowledge of the state of the tunnel and avoids subjectivity problems. These techniques may also function as a basis for the acceptance of new tunnels. Examples of the use of these devices for tunnel lining inspections on different infrastructures (metro, railway, roads) in Italy, UK, Spain and Japan will be presented.
