Underground engineering

Alternative route on S.P.3

Design of two two-lane road tunnels on main provincial road of Val Senales
Owner/client Studio Dr. Ing. Fischer (Merano)
Type of service Detailed Design; Works Management
Location Naturno
Period 1998 - 2002
Cost € 14.000.000

The need to keep users of the S.P.3 main provincial road through the Val Senales safe from the danger of falling rocks of various sizes led the provincial government to design an alternative route for the aforementioned road.

On account of the alpine valley landscape, the bypass mainly passes underground, through two tunnels.

From the design point of view, the fact the tunnels are placed in the rock wall meant carrying out a precise study of the stresses in the rocks in order to assess the ratio between the main stresses at the foot of the slope and estimate the degree of breakage of the rock affected by excavation.

Tunnel 1

800 meters long; Natural tunnels dug out of the rock.

Tunnel 2

330 meters long; Natural tunnels dug out of the rock; Plate walls with tie-rods for upstream opening.

Galleria 1 (imbocco Nord)
Galleria 2 (imbocco Nord)
Galleria 2 (imbocco Sud)

Owing to the facts mentioned above, the final design involved in-depth geomechanical investigations and analyses of the behavior of the rocks in the conditions before and after the works were carried out. It also involved:

- Establishing the static and technological dimensions of the natural tunnels to be dug through metamorphic rocks under a maximum ground cover of 120 m using traditional excavation methods;

- The static design of the artificial approach tunnels to the underground structures, which also involved works to make both the slope and road safe.