lots 6-7 of the Variante di Valico
As tall as a 5-storey building, “Martina” is the world’s largest tunnel milling machine used by Toto Costruzioni Generali to dig the “Sparvo” tunnel, the most demanding of the Variante di Valico, consisting of two carriageways for a total length of about 5 km (2,431m for the northbound barrel; 2,495m for the southbound barrel). Each carriageway houses 3 lanes of 3.75 m, connected by 10 by-passes, 2 of which are drivable, and is equipped with 17 rescue niches.
The mega milling cutter was acquired by Toto in 2010 from Herrenknecht AG with a total investment of € 53 million.
Martina “allows work to progress at speeds of more than 12 metres per day (against 15-20 metres per month obtained using traditional techniques) and eliminates the long time required for consolidation, excavation and unearth work, as well as losses associated with possible front releases. The use of automated excavation also drastically reduces the risks for the safety of workers who can operate in a protected environment.
The numbers of the TBM Martina
- Excavation diameter: 15.62 m (equivalent to a 5-storey building)
- Total length: 130 m
- Excavation area: 192 m³
- Thrust value: 39,485 t
- Total weight: 4,500 t
- Total installed power: 18 MW
- Annual consumption: about 62 mln kWh