Breakthrough at Gondar Station on Rome Metro B1On 03.12.2009 the 6.76m-diameter EPB TBM (odd track) entered the Gondar station of the B1 Metro line in Rome, having started its drive at Conca d'Oro station.The project was subcontracted to SELI by JV Salini Costruttori - Maire Engineering in early 2008 for a total of EUR50 million and includes the construction of 3 km-long twin tunnels lined with 35 cm-thick precast concrete segments in a 6+1 Universal design arrangement. Two EPB TBMs, designed by SELI and built by Herrenknecht, are in use under very high EPB pressure of 3-4 bars, backed up by Continental tunnel conveyors and vertical conveyor.Poor geology in sandy clay, tunnel depth up to 30 m, ground water pressure of 2.5 bars, the presence of old critical buildings and crossing of the Aniene River all combine to make the job difficult. The second TBM will reach Gondar station early in January, 2010. The two TBMs will then complete the excavation of the line, arriving in the Piazza Bologna station by October, 2010. Commissioning of the Bologna-Conca d'Oro section is scheduled for the end of 2011, while the Conca d'Oro-Jonio Ionian section is scheduled for December, 2012.Click it/31, here and here. Visit www.salini.it, www.selitunnel.com, www.herrenknecht.com, www.mairetecnimont.it and www.continentalconveyor.ca. 52/09.