Mont Blanc Tunnel: Deformation and Strain Monitoring

Mont Blanc dalle mesures contraintes déformations Cementys

Mont Blanc Tunnel : deformation and strain monitoring

Tuesday 30th March 2021

Project: Mont Blanc Tunnel’s under the road slab rehabilitation

Client: BOUYGUES TRAVAUX PUBLIC

Location: Mont Blanc Tunnel
Nature of the surveillance: deformations and strain

Project objectives:

The main objective resides in the total replacement of the tunnel’s slab from section PM5833 to PM6124 and PM6680 to PM7524. The total length is approximately 1135 meters divided into two sections: 291 meters and 844 meters, with very little impact on the traffic and the operations in general.

The new structure should be built to:

  • Ensure the tunnel more than 100 years of lifetime
  • Allow stability and durability performances in accordance with French standards.

Our team operates towards that goal by installing 400 sensors in the most sensitive parts of the structure. By ensuring constant monitoring of those sensors, our engineers can evaluate strain and deformation levels in the tunnel slab as well as the movements between the different parts of the structure.

The sensors are connected to our visualization software THMInsight. It allows every construction site actor to check in real-time the structure’s deformation level and to alert in case of an overtake of control thresholds. Therefore, both human safety and the tunnel’s durability are guaranteed.

Project’s key issues and difficulties:

In order to ensure constant traffic during these interventions, three teams will work simultaneously in the tunnel. Tests will be systematically done to check the proper installation of every element and safety conditions optimization.

Cementys solution:

The monitoring system established by our teams relies on the following elements:

  • 175 crackmeters
  • 200 deformation gauges
  • THMInsight visualization software
  • 24/7 monitoring
  • Real-time alerts
Cementys déformations monitoring Mont Blanc