Successful drive into the Piora syncline from Faido

Driving the Gotthard Base Tunnel through the Piora syncline is progressing well: the tunnel boring machine in the east tunnel has already cut through 74 percent of this geologically challenging zone. AlpTransit Gotthard Ltd expects cutting of the east tunnel through the Piora to be completed in mid-October 2008.

At the end of August 2008, the tunnel boring machine in the east tunnel was parked around 100 m ahead of the Piora syncline. AlpTransit Gotthard Ltd then drove a core bore with a diameter of approximately 10 centimetres through the Piora. The results of this bore confirm the forecast that was made based on earlier exploratory bores in this area: at tunnel level, the Piora syncline is about 150 m long and composed of dolomitic rock that is hard and bears no water.
Since September 29, 2008, the first tunnel boring machine has been traversing the Piora syncline. The average daily advance rate is around 10 m. To prevent the tunnel boring machine from becoming jammed under the high pressure conditions, steel rings are being installed at intervals of 1 m behind the cutting head. Also immediately behind the cutting head, a shotcrete seal is being applied to protect the cut surface. Finally, approximately 25 m behind the cutting head, a 30 cm thick shotcrete ring is being constructed.
Some 74 percent of the Piora has already been cut through. To date, the rock behaviour has been stable. There have been no indications of unacceptable deformations, and no water has been encountered. Provided that construction continues to progress at this good rate, the east tunnel will have crossed the Piora syncline as from mid-October 2008.
The drive in the west tunnel is currently 1,600 m behind the east tunnel. The tunnel boring machine in the west tunnel is expected to reach the Piora syncline in the first quarter of 2009.

Status of work on the Gotthard and Ceneri

Construction work on the Gotthard axis is still on schedule. On the Ceneri Base Tunnel as of October 1, 2008, at Sigirino 78% of the window adit had been excavated. There is currently no driving work in progress on the main tunnels.
On the Gotthard Base Tunnel as of October 1, 2008, of the total of 153.5 km of tunnels, galleries and passages, 118.4 km, or 77 %, had been excavated. At Erstfeld, both tunnel boring machines are advancing very well at
14 - 17 m per day. At Amsteg, concreting of the vault will be completed by the end of 2008. At Sedrun, driving in the west tunnel towards the south is progressing according to plan. Driving in the east tunnel is taking place in a geologically difficult zone which, at more than 100 m, is considerably longer than forecast. At Bodio, concreting the inner lining of both tunnels was completed in summer 2008.
Provided that all continues to proceed as planned, the main breakthrough on the Gotthard Base Tunnel will take place in the first half of 2011. Commercial operation of the Gotthard Base Tunnel with scheduled train services is planned to start at the end of 2017.