A Herrenknecht gigant reaches its target
Sparvo, Italy / Schwanau, Germany, September 6, 2013. The Herrenknecht tunnel boring machine needed about two years to construct the Sparvo Tunnel with its two parallel tubes of around 2.5 kilometers in length each. On July 29, 2013, the construction company TOTO Costruzioni Generali S.p.A. celebrated the final tunnel breakthrough with leading Italian politicians and numerous other guests. This meant that the Herrenknecht Earth Pressure Balance Shield “Martina”, with its shield diameter of 15.55 meters, is the largest tunnel boring machine in the world to successfully complete a project.
In view of the expected mine gases, designers had equipped the machine with explosion protection. Together with the client, local authorities and universities a sophisticated safety system had been developed. The entire belt conveyor on the tunnel boring machine has a double-walled housing and is pressurized so that the excavated material containing methane can be removed from the tunnel safely. In addition, fresh air was permanently fed into all areas of the TBM using an efficient ventilation system. Both the tightness of this casing and the gas concentration were monitored continuously.