01.03.2017 - Fault zone successfully overcome
The 'swimming mountain' has been overcome: the fault zone 'Raibler Rauwacke' was broken through at the end of January 2017. The rock formation consisting of water and mud will now be sealed and secured with a 60-centimetre ring of concrete. Drilling and blasting are due to continue at the building sites in Preda and Spinas on 1 March 2017.
Virtually unnoticed by the public, work continued intensely in the cavern at tunnel metre 1,300 during the winter break. The tunnel excavation through the frozen 'Raibler Rauwacke' was thus able to be successfully completed at the end of January 2017. But it will take until the end of March 2017 before the freezing sets can be switched off. By then the main tunnel will be sealed against the water and its high pressure. Finally an internal ring made of concrete 60 centimetres thick will be created which will structurally stabilise the tunnel. Only then can the freezing devices be dismantled and work started on other technical installations in the cavern.
The headwork on the Preda and Spinas sides is being restarted on 1 March 2017. Work goes on around the clock seven days a week. The breakthrough into the cavern at tunnel metre 1,300 from the Preda side is likely to take place in the second half of 2017. The headwork involves blasting. The enclosed video of a blasting shows exactly how this takes place. To date around 1,400 metres of tunnel, or around 24 per cent of the entire tunnel length of 5,860 meters of the new Albula Tunnel, have been excavated.