SIG is a scientific, not-for-profit association with approximately 650 members, that promotes, coordinates and spreads the results of studies and researches in the field of underground works.

It publishes the “Gallerie e grandi opere sotterranee/Tunnels and large underground works” magazine (in Italian and English).

The working groups are mostly focused on the participation to the international working group for the occasion of the International world tunnel Congress.

Railway tunnels

Milan-Naples High Speed/Capacity railway line, Bologna feed line

The construction of the underground station of Bologna Centrale (platforms 12-17)in an urban context is 90%. Excavation works are over.

Milan-Genoa High Speed/Capacity railway line

Five tunnels (40x2 km of underground route in total).Final design is started.

Genoa Bypass Railway Line

The work concerns:

  • A double track tunnel (2.8 km in length, 13 m in diameter)
  • 2 single track tunnels (2 x 1.4 km in length, 8 m in diameter).

Excavation works are in progress.

Brenner Base tunnel

Work includes the construction of two line (9 m dia.) bore and central exploratory/service tunnel (6 m dia.). Length of each tunnel is 55 Km. Excavation works are in progress.


Naples underground, Line 6 (Campegna – Porta del Parco extension)

The work concerns:

  • a single tube tunnel of about 3,800 m to be created via an EPB shield of 8.30 m in diameter;
  • 3 stations.

Excavation works is going to start.

Milan Underground, Line 4 Linate Airport-S.Cristoforo section)

The work concerns:

  • a running tunnel of about 11,70 km in length, to be bored by using two EPB shield of 6.36 m in diameter;
  • a running tunnel of about 3,70 km in length, to be bored by using an EPB shield of 9.15 m in diameter;
  • 21 underground stations.

Final design is in progress.

Milan underground, Line 5 (Garibaldi-San Siro/Harar section)

The work progress of the line twin tunnel (6,755 m in length and 6.8 m dia.) and of 10 stations is 50 %. The line twin tunnel is bored by using two EPB TBM.

Rome underground, Line B1 (Conca d’Oro-Jonio extension)

Excavation of the line tunnel (9.80 m in diameter) is over.

Rome underground, Line B (Rebibbia – Casal Monastero extension)

Line twin tunnel of 6.7 m in diameter, approx. 3 km in length, and two underground station. Excavation works are going to start.

Rome underground, Line C (S. Giovanni-Montecompatri/Pantano section)

Excavation works of line tunnels (18.5 Km in length and 6.75 m dia.)are over. Excavation works of 12 underground stations are in progress.

Rome underground, Line C (Venezia - S. Giovanni section)

Final design is in progress; excavation works of line tunnels (3 Km of twin tunnels, 6.75 m dia.) are going to start.

Road tunnels

Pedemontana Lombarda Motorway, Dalmine-Como, Gaggiolo pass connection

Two tunnels (Grandate and Morazzone, 2,450x2 Km total length, 16 m dia. Works are 60 %.

Modernisation of Motorway A1 Milan-Rome-Naples, Valico by-pass

Four twin tunnels (Val di Sambro, Grizzana, Quercia, Sparvo)(each tube about 180 m2 cross-section. Excavation of Grizzana and Quercia tunnels is over. Excavation of Val di Sambro tunnel is 65%. Excavation of the Sparvo tunnel (2.5x2 km in length, 15.55 m in diameter), done by using an EPB-TBM (the world’s largest TBM) is 70%.

Salerno-Reggio Calabria motorway

6° macro lot tunnelling works are in progress.

E90 motorway, SS 106 “Jonica” section, 11 tunnels.

Excavation works of the twin tunnels (6,671 km in total length, 13 m dia.) are over.

Quadrilatero (Umbria-Marche roadworks)

10 tunnels.

Tunnelling works are in progress.

A14 motorway, Widening of 5 existing tunnels from two to three lanes + the hard shoulder .Works are in progress.

Frejus safety tunnel

The works for the excavation of a tube about 8 m in diameter and 12.87 km in length are in progress.

New Colle di Tenda road tunnel

The project, which provides for the widening of the existing tube and the construction of a new 3,200 m long tube has been approved and financed by CIPE. Final design is in progress.

S.S. 212 “della Val Fortòre” and ex s.s.369 "Appulo Fortorina"

Work includes excavation of no. 4 tunnels, 15.20 m dia., and 2,700 m. total length). Excavation works of Cerzone and Fuciello tunnels are over. Excavation works of San Pietro and Monte Leone tunnels (approx. 1.2 km of total length) are in progress.

S.S. 106 Jonica (Sibari – Roseto Capo Spulico)

Ten twin tunnel; total lenght about 10x2 km. Final design is in progress.