- Location: Italy– Emilia Romagna – Forlì Province
- Client: Anas S.p.A.
- Project value: € 89.043.631
Works to build sections adjacent to the towns of Valbiano, Lago di Quarto and Taibo, in Forlì province.
The main works comprise nine viaducts having a total length of 11,700 m, one of which built using the steel-concrete composite system. In addition, two bored tunnels measuring a total of 5,050 m and a rockfall protection tunnel and other minor works.
The 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 excacvating these tunnels, a large number of problems are faced due to the the specific geomechanical characteristics of the soil which the tunnels run through. Excavation of the tunnels is mainly performed using explosives, with immediate consolidation along the tunnels face, application of fibre-reinforced shotcrete, continuous radial achore bolting and the installation of steel ribs.
In the event of specific difficulties, additional pre-consolidation works are performed consisting in:
- drainage works and fibreglass anchors at the tunnel faces in order to improve the soil consolidation prior to start excavation as well as horizontal jet grouting and installation of drainage pipes, for the purpose of securing the safety of excavation at the tunnel front and perimeter.
- 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.