ABSTRACT
The Isarco river underpass is the southern construction lot of Brenner Base Tunnel that will connect Italy and Austria with the longest railway tunnel in the world.
A solution with 4 tunnels underneath the Isarco river has been chosen to cross the fluvio-glacial loose deposit allowing the construction of 2 main tunnels and 2 interconnection tunnels. The design foresees heavy ground improvement works to increase both resistance and deformability parameters together with a strong reduction of permeability of the mainly gravel and sand with big cobbles soil; this has to be achieved coping with a high water table flow rate.
Works foresee vertical and horizontal jet-grouting, cement and chemical grouting, horizontal ground freezing. In order to achieve the design requirements the Site Supervision has been involved in controlling and analyzing specific tests and in situ trails field together with specific control procedures.
