Manufacture of the largest EPB TBM for a European project, the third largest the world has ever seen, and the second largest ever manufactured by Herrenknecht of Germany, is complete.
Representatives of the client, the Italian Highways Authority Austostrade per l’Italia S.p.A, and its appointed contractor Pavimental S.p.A. gathered at the Herrenknecht factory in Schwanau to complete a comprehensive technical inspection and to then formally accept the 4,800-tonne mega-machine. The official ceremony took place last Monday (29 August).
At 15.87m in diameter the titanic machine is 25cm larger than the previous European record-holding shield – the 15.62m EPB, also manufactured by Herrenknecht, for excavation of the 2.5km twin tunnels at Sparvo as part of a phased renewal and upgrade of the A1 highway between Bologna and Naples.
The latest mega-machine to come out of the Herrenknecht factory is the largest the company has ever manufactured in its European facilities, and will be used to excavate the 7,528m Santa Lucia Tunnel in the Apennine mountain range, located between Barbarino and Firenze Nord (Fig 1). A 59km stretch of the A1 between Barbarino di Mugello in the north, and Firenze Incisa Valdarno in the south, is being widened in four lots (one of which is completed) through the construction of up to three new lanes for southbound traffic, with the existing four-lane highway, two in each direction, being turned into the northbound route.
The machine, which will drive through a heterogenous geology, features a drive power of 8,750kN, and a torque of 101,296kNm. The contractor for the job, Pavimental, is 20% owned by the client company, and 0.6% owned by Italian company Astaldi.
In the coming months, 13 Herrenknecht TBMs will be operational in Italy – eight of them measuring more than 8m in diameter. On the A1 route alone a total of 44 new road tunnels are planned – including the Santa Lucia Tunnel. The route will be opened to traffic in 2019.
Only two machines in the world have been manufactured to a larger diameter than the enormous 15.87m EPB that will excavate the Santa Lucia Tunnel– the 17.48m Hitachi-Zosen EPBM that is currently excavating the Alaskan Way Viaduct Replacement Tunnel in Seattle, USA; and the world-record 17.6m Herrenknecht machine that was built in the company’s Chinese factory for the currently under construction Tuen Mun–Chek Lap Kok subsea highway link in Hong Kong.