ALLOCCO TUNNEL

Length: Northbound barrel (55.69+1,655.07); Southbound barrel (72.12+1693.33)

Excavation section: 155 m³   

Digging radius: 7.80 m

Coating thickness: 60 cm

Consolidation: front n. 15÷50 VTR L=15m – contour n. 35÷55 VTR high pressure injected L=15m

Driveways and pedestrians by-passes: n. 4 pedestrians + n. 1 driveway

The Allocco tunnel (double-barrel tunnel) measures a total length of 3,480 m, divided into the two North (1,710 m) and South (and 1,770 m) carriageways. The type of excavation used is the traditional one with a poly-centric section of 155 square meters with a excavation radius of 7.80 m and a final lining of 60 cm. The most common type of advancement section involved pre-consolidation at the front with n. 15÷50 VTR 15m long and 5 m overlap, while on the contour high pressure injections of cement mixes are added in several phases, n. 35÷55 VTR valves 15 m long and vacuum drilling of 2 m, centring 2 IPN 160/1,00÷1,50m and spritz 25÷30 cm thick. 4 pedestrian bypasses and 1 driveway pass have also been built.