Gastau tunnel is 5.05km-long and 6.19m diameter. The first stretch, 210m-long starting from the portal has used a drill and blast method and the second stretch, 4840m-long, used a double shield TBM. More then 80% of the tunnel length runs through gnessic and granite formation (the so-called Pico do Papagaio complex), while at the portal, the excavation was in loose materials (weathered rock and residual soil). The tunnel will host initially one pipeline (28” in diameter) for conveying gas through the mountain; future, it may host some additional supply lines (for a maximum of 3) with similar diameter, according to the extraction level and national demand of natural gas in Brazil.

Design of the mechanized tunnelling solution, including dimensioning of the precast segmental lining. Follow-up on site of the mechanized excavation, by analysing continuously the TBM performance parameters through the implementation of PAT (Protocol of Advance of Tunnel) with definition of risks, counter measures and corresponding mechanisms of activation.