Messina, journey aboard the 900 ton “mole”: this is how 15 meters of tunnel are built every day


By John

It's written “Tunnel boring machine”, it's read mole. To carry out the most important work of the last fifty years, which will cross two provinces, four will come into action.
The excavation of the tunnels of the new double-track, high-capacity Giampilieri-Fiumefreddo railway line is in fact entrusted to technologically advanced machines arriving from China, built for the group Webuild-Pizzarotti.
One of these, called “Igea”, is already at work to build the “Sciglio” tunnel, 9.3 km long, which will connect the Nizza di Sicilia station with the Agrò viaduct in Savoca.
We were on board during a visit which was also attended by the government commissioner of the work, Eng. Filippo Palazzo, the contact person for the “Rfi” project, Eng. Maurizio Infantino and the Italferr project manager, ing. Salvatore Vanadiato discover the “secrets” of the tricolor giant, which has a diameter of 9.36 meters and weighs approximately 900 tons.
This is a machine that adopts the most advanced technologies in terms of environmental sustainability, as it is capable of reducing emissions during tunnel excavation and is also of the Dual Mode type, i.e. capable of excavating both with earth pressure in loose terrain and in open mode on rocks. An extremely innovative giant mole, 136 meters long, which advances in the ground thanks to a milling head on which the digging tools are mounted, which rotate at a speed that can vary based on the hardness of the surface, but which is also a mobile factory: during the excavation, in fact, it transports the debris out of the tunnel and assembles the linings in parallel, large rings composed of prefabricated ashlars 1.80 meters wide (made in the new Webuild factory in Belpasso) which stabilize the ground, glued together with special resins , and ensure that, after the passage of the “Tbm”, the tunnel is practically ready.