End of Tunnelling on Apennine Section of Bologna-Florence High Speed LinkThe breakthrough of the Vaglia tunnel on 21st October, 2005 marks the end of tunnelling on the Apennine section between Bologna and Florence on the new high speed and high capacity line from Milan to Rome and Naples. A big and nice celebration was attended, among others, by the tunnelling crews, Pietro Lunardi, the minister for infrastructure and transport, Elio Catania, the president of the Italian railways, and Antonio Savini Nicci and Riccardo Bonasso, respectively directors of TAV and Italferr.The 18,561 m Vaglia tunnel is the longest on the new line. The alignment from Bologna to Florence spans 78.5 kilometres, whereof 73.3 km in tunnel (93%). Now all the route has been cut through, finishing works of the tunnel walls can begin prior to track laying works. To achieve this extraordinary piece of engineering, unique in the world by its dimensions, complexity and financial cost (in 5 ½ years, over 100 kilometres of tunnel has been bored, whether it is 140 sq m main tunnels or access and service tunnels, in geological conditions among the most difficult and complex in the world), 31 worksites have been opened: 10 base camps for the staff and 21 tunnelling job sites. More than 3,500 people have been employed seven days a week, 24 hours a day. There are nine tunnels on the line between Bologna and Florence, with short stretches in the open air and a 10 km parallel service tunnel, most of which runs parallel to the final section of the Vaglia tunnel, and 12 access adits which will be used not only for rescue and escape but also for maintenance of the line. At Vaglia progress was made with hydraulic breakers. Following no more than 2 m behind the cut face, temporary support was provided by steel arches at 1.5 m to 2 m centres. A layer of 200 mm to 300 mm of steel fibre-reinforced shotcrete has then been sprayed onto the walls.Tunnelling has been executed by the general contractor FIAT/CAVET, a consortium of companies headed by Impregilo, Italy's leading contractor, and including CMC, Maire Engineering and CRCPL. The design of all underground structures has been achieved by Milan-based Rocksoil on behalf of Maire Engineering. Visit www.rocksoil.com, www.impregilo.it, www.cmcra.com and www.maireengineering.itThere is no doubt that the project has been a pilot experience for all the sector of major infrastructures. A wide and inhomogeneous variety of rock masses, with variable coverage ranging from 0 to 600 m, has been dealt with and tunnelled: from flysch formations to clays and fine claystone to loose and unstable ground, characterised in some cases by water ingress and presence of gas.Both the design and construction of the tunnels comply with quality assurance and with the principles of Rocksoil's ADECO-RS approach. This Italian acronym stands for Analysis of COntrolled DEformation in Rocks and Soils. It consists of the systematic application of full face tunnelling, further to the reinforcement of the ground ahead of the face beforehand. It allowed to employ big and powerful machinery, highly versatile, but above all, to cope with excavation conditions often difficult, it made it possible to industrialise tunnelling (progress reached peaks of 2,000 m/month) and to advance within budget and on time, always guaranteeing the highest safety conditions.In fact, this tunnelling methodology streamlines the full production cycle and reduces any possibility of discretionary power during the construction phase. It has permitted significant benefits in terms of safety and prevention, two issues which have been given special attention from the design phase. At all the sites, an emergency rescue service set up by the contractors and the public administrations of the Emilia Romagna and Tuscany regions has been activated. A sick bay has been installed at every site and the efficiency of communication systems (radio and telephone), rescue activation, coordination between the tunnel sites and external services (doctors, ambulances, rescue helicopters) has played a significant role.Now tunnelling in the Apennines is completed, work on the new line still proceeds to build the connections with the Bologna and Florence stations. Click it/22 and here. To view a video, click www.tav.it/1/default.asp?id=68&codice=1&codice1=002&codice2=001&codice3=002 49/05. Click to enlarge