Crack monitoring and evaluation model of unreinforced tunnel linings
RIBET includes the evaluation and systematisation of crack patterns of unreinforced tunnel inner shells, a methodology for the measurement-based assessment and prognosis of the hazard also behind lining panels.
A comprehensive compilation of conceivable phenomena and causes for cracks in the tunnel was compiled and serves as an aid for the competent engineer in his comprehensible interpretation of crack patterns. The developed crack catalogue is also a basis for a future (semi)automatic crack evaluation.
The applicability of the distributed fibre-optic crack monitoring system developed in the course of the laboratory tests for monitoring existing tunnel linings could be verified under real conditions in the Tauern Tunnel with a one-year measuring campaign. Thus, crack detection and crack width measurement (accuracy 0.15mm) will be possible in the future even behind cladding panels.
When using matched fibres and adhesives, the cracks can be reliably detected. They have a similarly good accuracy as conventional crack width sensors. Measurement layout and interval were derived based on the crack catalogue and the potentially interesting crack phenomena contained therein. Essential influencing parameters for the evaluation (temperature, crack movement) were investigated, strategies for the detection and interpretation of the crack patterns were derived. The evaluation can also be automated.
Funded by the Federal Ministry for Climate Protection, Environment, Energy, Mobility, Innovation and Technology (BMK) and the Austrian Research Promotion Agency (FFG) as part of the Mobility of the Future/VIF 2017 programme.