|Owner||ROME MUNICIPALITY - ROMA CAPITALE|
|General Contractor||METRO C s.c.p.a.|
|Duration of works||2014 - 2016|
During the construction of the new Line “C”, many problems had to be solved in order to preserve the priceless heritage resources encountered underground. Some important archaeological remains, brought to light during the construction of the New San Giovanni Station, made it necessary to change the original project. The station was built at a depth of 30 meters; diaphragm walls were excavated down to a depth of 55 meters until the impermeable layer of Pliocene clays was reached. Moreover, two traditional tunnels were excavated beneath Line “A”’s existing station by means of special consolidation techniques.
In order to allow trains to regularly run to and from the existing station’s line “A”, temporary structures for rail support were installed next to Line A’s platform level. Said structures (steel bridges founded on micropiles) will operate during the excavation of undercrossing tunnels. Moreover, a suitable structural monitoring system was devised.
Consolidation and impermeabilization of both excavated tunnels was achieved via the Artificial Ground Freezing process. This method is employed for excavations in difficult conditions below the ground water level in the presence of loose soil or fractured rocks. The Freezing Method is the best choice whenever works are carried out in sensitive urban areas, in order to ensure the greatest possible safety degree as far as both workers and existing surface structures are concerned.