Works to build sections adjacent to the towns of Valbiano, Lago di Quarto and Taibo, in Forlì province.
- Client: ANAS S.p.A.
- Contract amount: € 89,043,631
The main works involve nine viaducts of a total length of 11,700 m, one of which built using the steel-concrete composite system, two bored tunnels measuring a total of 5,050 m, a rockfall protection tunnel and other minor works. Construction of the two tunnels running side-by-side, each measuring approximately 2,500 m, represents the most important and technologically
complex part of the road works. Indeed, while building said tunnels, a large number of problems are dealt with, caused by the specific geomechanical characteristics of the soil the tunnels run through. Excavation of the tunnels is mainly performed using explosives, with immediate works to consolidate bores using fibre-reinforced shotcrete, continuous anchoring through radial bolting and the installation of metal ribs.
In the event of specific difficulties, additional pre-consolidation works are performed consisting in:
- drainage works and fibreglass bolts at the tunnel faces in order to improve sealing, as well as forepoling using valved, grouted pipes in order to perform preliminary consolidation of the contour prior to excavation;
- sub-horizontal jet-grouting and drainage works, performed beyond the tunnel face, in order to improve sealing of the tunnel face and of the section of earth around the excavation site.