North-West Ring Road of Merano - 2nd Lot: Cut&Cover Tunnel

Following a brief description of the context and of the project as a whole, the report presents the solution adopted for the excavation of the Cut&Cover Tunnel planned at the beginning of the 2nd lot, before the excavation of the mining method tunnel. The Cut&Cover Tunnel, 136 m long, will house the main axis, characterized by a platform with a total width of 8.5 m (two lanes of 3.5 m plus two docks of 0.75 m) and two ramps, one for the entrance and one for the exit, with lane widths of 5.2 m and 5.5 m respectively. The geometric complexity and the resulting size of the work, as well as the boundary conditions typical of a highly anthropized environment, led to a top-down excavation method, up to a depth of approximately 20 m, with large diameter (1.2 m) perimetral piles, 1.5 m spacing and intermediate 1,0 m piles, the casting of the roof slab in cast in situ reinforced concrete and temporary tie rods during the lowering phases of the excavation, before the construction of the inner shell in cast in situ reinforced concrete.