Gotthard Base Tunnel – Faido Section: Water Ingress in Tunnel Drive

Since the end of May 2010 there has been increasing water ingress into the east tunnel of the Faido section. The water originates from the fissures traversed by the drive. Because of the water ingress, increased machine maintenance must be performed, particularly on the electrical components. The water ingress also hinders driving because more frequent interruptions become necessary for special drillings.

As Renzo Simoni, Chief Executive Officer of AlpTransit Gotthard Ltd, explained today at the Swiss Tunnel Congress 2010 in Lucerne, the planned final breakthrough of the Gotthard Base Tunnel on October 15, 2010, is nevertheless not endangered at present: „I have, however, always pointed out that negative surprises are still possible and could delay the date.“

The water ingress into the east tunnel currently varies between 30 and 90 litres per second. The underground water is being drained off as normal and flows through the water processing systems. If, after processing, the water still contains an excessive amount of suspended material, it cannot be discharged into the Ticino. It is then discharged onto the surrounding overgrown areas to drain into the ground according to the approved process for water processing.

In the meantime, the campaign to explore the rock fall in the west tunnel has reached an advanced stage. The excavation and support work on the injection niche has been completed. The gel injections to protect the tunnel boring machine have been successfully inserted. The drillings for the cement injections are now being made. The reverse drive has reached its planned length of 85 m. If everything proceeds as planned, the tunnel boring machine in the west tunnel will be restarted in mid-July 2010.

AlpTransit Gotthard Ltd is the constructor of the Gotthard axis of the New Rail Link through the Alps with base tunnels through the Gotthard and Ceneri. Established in 1998 as a subsidiary of Swiss Federal Railways, the company now employs around 140 people at its headquarters in Lucerne and its branches at Altdorf, Sedrun, Faido and Bellinzona.