Breakthroughs at Marche-Umbria quadrilateralOn 20.07.2011 breakthrough was achieved in Genga municipality on the SS76 tunnels Valtreara (846 m with 388 m in cut/cover) and Gattuccio (294.50 m with 61.50 m in cut/cover). Excavation started in December, 2010 and April, 2011 with a 3 m/day average advance. The previous day, breakthrough of the north tube completed the 1,101 m-long Belfiore tunnel on the SS77 Val di Chienti in Foligno municipality. Other twin-tube tunnels completed in the previous two months were: La Franca (1,075 m in Leggiana), La Palude (1,226 m in Colfiorito) and Serravalle (1,341 m in Serravalle di Chienti).On 20.07.2011 excavation of the 3.8 km-long, single-tube Gola Rossa tunnel in Serra San Quirico (AN) municipality on the SS76 reached 1,250 m. This is a complex work that requires advanced drilling techniques because of the presence of massive limestone that characterizes the entire alignment. Click here, here and it/116. Visit www.quadrilaterospa.it. 30/11.