On 21.01.2016 at 12.00 noon and about 700 m away from the north portal at Camorino, the final breakthrough in the 15,289 meter long west tube of the Ceneri Base Tunnel took place. The breakthrough was accurate the horizontal deviation was 2 cm and vertically 1 cm.
Speeches were given by Renzo Simoni, Chief Executive Officer of AlpTransit Gotthard Ltd, Duccio Astaldi, Head of the Condotte Cossi Consortium, Claudio Zali, the Ticino Director of Construction and Peter Füglistaler, Director of the Federal Office of Transport.
The Ceneri Base Tunnel like the Gotthard Base Tunnel, is composed of two single track tunnels linked by 48 cross passages, each one is 325 meters and approximately 40 meters long.
The construction was composed of three lots, a 790 meter lot at the North adit (Vigana), a 360 meter lot at the South adit (Vezia) and the main lot from Sigirino towards these two adits. As a result of the complex geology, the Ceneri Base Tunnel was excavated entirely by drilling and blasting.
Through out the building of the tunnel the rock’s behavior has not followed the geological forecasts. The progress from Sigirino was delayed by 12 months as a result.
Most of the excavations were performed simultaneously in both directions from the intermediate heading at Sigirino. Vigana and Vezia, had inward drives they were excavated this way to minimise time and costs. Construction of the Ceneri Base Tunnel produced about 8 million tonnes of excavated rock. First preparatory work was performed in 1997 with the 3.1km long exploratory tunnel. And in 2008, a TBM finished the excavation of the 2.3 km Sigirino access adit. At the end of this adit are two underground caverns which, from 2010, were the starting points for the main drives running south and north. The second and final breakthrough, in the 15,452 m east tube, will take place at the beginning of next week to date 24 meters remain to be excavated.
In the coming months, further work will be done on the tunnel lining. By the end of 2016, all tubes and adits will have been completely lined and concreted. The railway infrastructure system is also being fitted throughout with mechanical and electromechanical systems such as doors, ventilation systems and building management systems. These ensure that the railway tunnel can be safely operated and maintained.
The Ceneri Base Tunnel is scheduled to become operational in December 2020.
The opening of the tunnel will reduce the journey time between Locarno, Lugano and Bellinzona. Click here and ch/14 for tunnel builder archive. Visit www.alptransit.ch. 03/16.
