Gotthard approaches final breakthrough, Ceneri starts main drive

The AlpTransit Gotthard project is on course. In the Gotthard Base Tunnel, the final breakthrough will take place in autumn 2010. In mid-March 2010, the main drive of the Ceneri Base Tunnel began. At the premiere of the AlpTransit annual film for 2009 on March 31, 2010, Renzo Simoni, CEO of AlpTransit Gotthard Ltd., gave information about progress on construction of Switzerland’s largest-ever construction project.

To date, almost 95% of the total of approximately 151.8 kilometres of shafts, passages and tunnels of the Gotthard Base Tunnel have been excavated. Civil engineering construction, concreting, and lining work in the Sedrun North, Amsteg and Bodio sections are complete. Final breakthrough in the east tunnel between Faido and Sedrun is scheduled to take place in the autumn of 2010. Up to that point, the tunnel boring machines must cut a further approximately 2.5 kilometres. As from mid-2010, installation of the railway infrastructure systems will start in the west tunnel at Bodio. The systems include the railway tracks, catenaries, telecom systems and electric power supply. To handle the logistics of installing the railway infrastructure systems, in the last few months the installations site was set up at Biasca, a few kilometres to the south of the south portal. Assembly workshops, a concrete production plant, offices and accommodation for workers have been erected on the site.

Large, chimney-like hollow space
In the west tunnel of the Gotthard Base Tunnel, approximately 600 metres behind the drive in the east tunnel, the tunnel boring machine has been stationary for around four weeks on account of a rockfall. During this period, test bores have been performed to determine the size of the hollow space that has formed, as well as the length of the interference zone. The bores have shown that the interference zone is much larger than was assumed in the first days after it was encountered. The hollow space of the interference zone that has been investigated extends in the form of a chimney to a height of at least 40 metres above the tunnel invert. The complete volume of the hollow space is estimated to be approximately 3,000 cubic metres. A substantial part of the hollow space that has been investigated is still filled with broken rock. The length of the interference zone is between 6 and 10 metres.

To enable the tunnel boring machine to resume driving, in the next few weeks the loose area in front of the cutting head will be solidified with cement through a grouting tunnel from the east tunnel which runs parallel to the west tunnel. This will take about three months. The interruption in driving will have no effect on the time schedule or on the commissioning of the Gotthard Base Tunnel at the end of 2017.

Progress on the Ceneri Base Tunnel
On the Ceneri, a milestone was achieved with the first blast at the Sigirino intermediate heading in mid-March 2010. The miners were given the go-ahead for the main drives to the north and south. From the north portal at Vigana, near Camorino, driving is proceeding under the A2 motorway. Driving in the opposite direction from the area of the south portal at Vezia will begin in mid-April 2010.

Annual film 2009 – 35 minutes of tunnel construction on DVD
The progress of construction on the Gotthard and Ceneri base tunnels is documented by film teams commissioned by AlpTransit Gotthard Ltd. Each year this results in an annual film, which, in about 30 minutes, documents the most important milestones on the NRLA construction sites of the Gotthard and Ceneri, as well as the progress of the miners. The annual film for 2009 is now available in three language versions (German, Italian, English). The DVD, which costs CHF 30, can be ordered on the Internet (http://www.alptransit.ch/?id=66) or purchased directly at the AlpTransit information centres in Erstfeld and Pollegio or the offices of AlpTransit Gotthard Ltd. in Lucerne, Altdorf, Sedrun, Faido or Bellinzona. The DVD is also available at the RailShop in Lucerne railway station.

Review of 2009: Work on the Gotthard

  • In both tunnels of the Erstfeld section, the tunnel boring machines broke through to the Amsteg section. On the overground section to the north, work began on various structures such as bridges, underpasses and culverts.
  • The Amsteg-Sedrun section is ready for installation of the railway infrastructure.
  • In the Sedrun section, the drives in both tunnels to the south are achieving daily advance rates of 6-7 metres. Fitting out of the multifunction station is in progress. The north section is ready for installation of the railway infrastructure.
  • In the Faido section, the northbound TBM drives crossed the boundary between the cantons of Ticino and Grisons in September 2009. The final work on the multifunction station is being performed at the same time as driving continues.
  • The west tunnel of the Bodio section is ready for installation of the railway infrastructure. The east tunnel continues to serve for supply to, and disposal from, the construction works in the Faido section.
  • On the overground section to the south, the groundbreaking ceremony for the new Swiss Federal Railways control centre at Pollegio took place at the end of November 2009. At Biasca, the installations site for the railway infrastructure was set up.

Review of 2009: Work on the Ceneri

  • At the north portal near Vigana, work began on tunnelling under the A2 motorway.
  • At the intermediate heading at Sigirino, the underground installations cavern was constructed and the installations site for the main construction lot was prepared.
  • At the south portal at Vezia, the preparatory work on the construction site pit was completed.<//span><//span>