Investigation of the Concrete Lining after the Mont Blanc Tunnel Fire

After the Mont Blanc tunnel fire, investigations for assessing the damage to the concrete lining were performed with the objective of determining the need for repairs. It was an opportunity to test new methods. Two innovative methods were tested: colour measurements inside the lining, and the Modal Analysis of Seismic Waves (MASW) method, normally used for soil investigation. These two methods are presented in this paper. Some results from other more classical methods are given, showing results in good accordance. From the identification of burnt concrete to the measurement of concrete thickness, the MASW method is under development for other applications in the world of tunnels like impervious membrane position.