In spring 2010, a geological interference zone brought the tunnel boring machine (TBM) in the west tunnel of the Faido section to a standstill. The miners have now freed the cutting head of the gigantic boring machine. As a result, the TBM can resume driving towards Sedrun.
On March 4, 2010, in the west tunnel of the Gotthard Base Tunnel a rock fall occurred about 9 km from the multifunction station at Faido. Driving had to be suspended. Test bores were performed to determine the size of the hollow space that had formed as well as the length of the interference zone.
To enable the tunnel boring machine to resume driving, in the last few months the loose area in front of and above the cutting head of the machine was solidified with cement through an injection niche from the parallel east tunnel. At the same time, also from the east tunnel, a further tunnel was excavated to the west tunnel and then driven backwards so that on July 22, 2010, the cutting head of the tunnel boring machine was freed. On the following day the TBM resumed driving in the west tunnel in the direction of Sedrun. By the summer holidays at the End of July 2010, the interference zone will have been completely cut through.
The construction costs for repairing the interference zone are largely included in the work contract. The standstill of the machine in the west tunnel does not cause a delay in the time schedule of the Gotthard Base Tunnel. It also does not endanger the planned final breakthrough in the east tunnel of the Gotthard Base Tunnel on October 15, 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 in Altdorf, Sedrun, Faido and Bellinzona.