Victoria sinks her teeth in

Victoria sinks her teeth in

Feb 4, 2015  | Civil engineering 

Victoria sinks her teeth in
(Photo by: Metrostav)

The first metres of the more than four-kilometre-long Ejpovice tunnel have been driven by the team headed by Metrostav’s Štefan Ivor today.

The largest TBM tunnel-boring machine in the Czech Republic, named Victoria, with a head diameter of almost 10 metres, has sunk her teeth into the shale on Homolka Hill near Kyšice, to appear once again near Potoční Street in Pilsen – Doubravka in about ten months. Afterwards, it will return to the starting point, where it will begin the construction of the second (northern) tunnel tube of these underground works, which should be completed in 2017.

The construction of two single-track tubes, which will have a length of 4,150 m and will be interconnected by passageways, is the centrepiece of the Rokycany – Pilsen Railway Line Modernisation Project, as set out by Pavel Surý, Director General, Railway Infrastructure Administration, during the ceremony to christen the machine. It is being implemented by the Consortium of Metrostav and Subterra, and should result in reduced running times and improved railway traffic safety. Once the modernisation of the entire railway line between the capital city and Pilsen has been completed, the travel time by train should take less than one hour. At the same time, passenger comfort will be improved, and a maximum line speed of up to 160 km/h will be achieved.

“After years of delay, we are glad that the modernisation of this important section of the railway line has finally begun, and that we have the opportunity to take it on jointly with Subterra,” commented Roman Fuksa, Director, Division 5, Metrostav, on the same occasion. The tunnelling and all of the work around the machine are ensured by 100 workmen and 24 technicians, who work in two alternating 12-hour shifts. “Approximately 12 people work at the machine itself, while another 15 people work with supporting technologies,” said Štefan Ivor, Head of Tunnelling. Once the machine passes through the hard spilite under Chlum Hill, the current railway line will have been shortened by more than six kilometres.

The tunnels are being driven by a special shield manufactured for Metrostav by Herrenknecht, based in Schwanau, Germany. It is 114 m long, weighs 1,800 tonnes, and with a head that rotates at a maximum speed of 4.5 revolutions per minute, it is able to bore up to 15 metres per day. The machine works as follows: To begin with, the machine excavates two metres of soil, and then stops. Then, under the shield envelope, it assembles a two-metre wide ring of final lining, and places it into the freshly bored section. As soon as the lining ring, with an internal diameter of 8.7 metres and a weight of 60 tonnes, has been completed, the shield continues forward in the same way. Excavated rock, the total quantity of which will amount to over 600,000 m3, is removed to the surface by belt conveyors, which will measure almost five kilometres in length in the final phase.

The project is co-financed from the Cohesion Fund under the Transport Operational Programme, where subsidies amount to 76.44% of eligible project costs, which translates into a maximum of CZK 3,419,440,199. Domestic funding is provided by the State Fund for Transport Infrastructure.

Via Metrostav
Image,video ©: Metrostav