Tunnel de Saverne
 

Full service for high-speed tunnel construction

The task

The “Tunnel de Saverne” passes under the Vosges and represents a core section of the high-speed rail route from Paris to Strasbourg, reducing travel time by 30 minutes. The project requires excavation for two parallel tunnel tubes through changeable geological conditions. The French tunnel builders opt for tunnelling technology and service power from Herrenknecht.

The Herrenknecht service solution

Even the tunnelling technology for building the “Tunnel de Saverne” is unique. This project sees the Multi-mode TBM, which can be driven in both EPB mode and in open hard rock mode with discharge via a tunnel belt conveyor, being used for the first time. For switching between modes, all that is needed are some adjustments at the cutting wheel. The conveyor belt and the screw conveyor remain installed on the machine in both modes.

Herrenknecht also provides the customer with support in the form of a full-service package. After breaking through the first section, the TBM is disassembled and transported back through the tunnel to the launch portal. This requires the use of a special custom-built transport wagon enabling almost the entire cutting wheel to be transported in one piece. Furthermore, expert Herrenknecht service personnel is available on site during the entire project term in order to actively support and advise the customers in any tasks arising.

Real improvements are developed by working together. The disc cutters are modified specifically on the basis of experience gained during tunnelling support along the initial section. This gives rise to the use of a new type of cutting ring while driving the second tube which reduces wear by more than half, significantly reducing the number of disc cutters changes required and accelerating advance accordingly. The site teams achieve daily best performances of up to 46 meters and weekly best performances of up to 250 meters. This is yet more impressive proof of the fact that Original Herrenknecht Services enable speedy and constant tunnelling.

Project advantages

• Swift restarting of the second tube thanks to efficient transport back through the completed tunnel 

• Project-specific adaptation of the disc cutters leads to significantly lower wear and therefore fewer change intervals.

• Tunnelling support provided by experienced supervisors helps the customer to manage the project more smoothly overall.

„While driving the first tunnel, we saw how we could save time and money on the second. The result: we achieved 60 percent fewer tool changes.“

Daniel Roussel, Machine Engineer at Spie Batignolles

View project movie