Terzo Valico dei Giovi - Genoa Junction
A new high-speed railway line that will strengthen connections between Northern Italy and the rest of Europe
Start of works
Data updated to September 2021
Terzo Valico: a journey on a 53 km long line, 37 of which in a tunnel
The Terzo Valico is a new high-speed/high-capacity line that strengthens connections between the Ligurian port system and the main railway lines in Northern Italy and the rest of Europe. Once completed, it will become Italy’s longest railway tunnel.
The work is part of the European Rhine-Alps Corridor which provides for the enhancement of the Genoa-Basel-Rotterdam / Antwerp railway axis of the TEN-T network, the European project to efficiently connect the most densely populated European regions.
Works involve 12 municipalities between the provinces of Genoa Alessandria, crossing the regions of Liguria and Piedmont, reaching Milan.
The new high-capacity railway line is a route that develops largely underground. Starting from Genoa, the first section, the so-called Valico Tunnel, develops 27 kilometres into the tunnel, making it Italy’s longest underground railway route.
If we also consider the additional underground works, the unique Terzo Valico – Genoa Junction project involves the construction of 90 kilometres of tunnels.
As a whole, the line features two twin single-track tunnels, within which the trains can reach a speed of 250 km/h. The new line will subsequently be connected to the existing lines through four interconnections: the Voltri Interconnection, the Genoa (Bivio Fegino) one, and the Novi Ligure and Tortona ones.
Compared to the total 90 kilometres of tunnels built, 28 of these were excavated with TBMs. The remaining 62 using traditional methods.
During the excavation phases, the complexity is twofold: on one hand, the use of sophisticated excavation techniques, specific to the geological features of the mountain; on the other, managing the huge volumes of spoil (the loose earth and the rocky fragments from the excavation works).
Therefore, the excavation techniques had to take into account the variable features of the mass which, at least in the Ligurian section, has poor geomechanical characteristics, requiring the use of traditional methods (hammer demolition or through explosive) for the high excavation roofs, and not TBMs.
Construction sites were opened along the entire route. They allow for a parallel advancement on over 30 excavation fronts, through 24/7 uninterrupted activity.
To guarantee these levels of operation, the construction sites settle and adapt to the territory and its conformation: in an extended like the Terzo Valico one, the construction sites are installed and adapted to very different contexts, ranging from urban to mountainous, passing through hills and flat land.
Circular economy principles in the Ligurian mountains
Mountain excavations, which were necessary to build the tunnels of the Terzo Valico, involved collecting an enormous amount of excavated materials. A complex disposal method was specifically studied for this purpose.
Environmentally compatible solutions have been adopted for their logistic management, in a circular economy perspective. A conveyor belt system, a line in the line one, which allows aggregates to be loaded and transported to the warehouse was, in fact, implemented.
By way of example, the Cravasco site, to manage one million cubic metres of excavated materials, a 2-kilometre-long conveyor belt system, capable of carrying up to 800 tonnes of material per hour, was created. In this partly spectacular journey, due to the mountainous features of the territory, a 260-meter-long stretch was covered with a flying belt. The latter, suspended in the void, at a height of 9 metres, from the ground, allows a direct connection between the site area and the quarry.
This way, the excavated spoil was loaded onto the belts, and transported directly to the final depot, reducing road transport and the related atmospheric emissions.
The Genoa Junction: a fundamental hub for connections between the port of the Ligurian capital and Northern Italy
The infrastructural upgrading of the Genoa junction, a strategic accessory to the new High Speed/High Capacity line, will ensure connecting the last mile between the Terzo Valico dei Giovi and the historical Port of Genoa, allowing direct connection for freight trains departing and arriving from the port, also allowing to separate the traffic flows between regional trains and long-distance ones, with a consequent potential increase of the regional and metropolitan train offer.
The Port of Genoa will become an access hub to the Rhine-Alpine Corridor, intercepting the commercial traffic that goes from the Far East to Europe, with the aim of saving about 5 days of navigation compared to the Northern Sea ports.
The Genoa railway junction project will run mainly underground. It will involve building three natural tunnels: the new single-track San Tomaso (1,500 metres long); the New Cristoforo Colombo (1,409 meters long); and finally, the Polcevera Tunnel (2,167 meters long).
Webcam 1 - Construction site "Libarna", Serravalle Tunnel, south entrance
Live from construction site
Webcam 2 - Construction site "Moriassi"
Live from construction site
The sustainable way in future mobility
Asbestos in the mountains and the safety of workers
All the tunnels of the Terzo Valico pass through a highly complex geological-structural context. Asbestos in its natural state was found in certain areas, in fact, during excavations. Although of biological origin, and non-polluting for the environment, if absorbed by the human body it can be carcinogenic.
This led the Cociv Consortium – of the Webuild Group to put its maximum effort into ensuring everyone’s safety, identifying the sources of diffusion and constantly monitoring the guard levels.
To avoid any worker risks, sophisticated suction ventilation systems have been installed in the construction sites, which on the one hand suck the air from the excavation fronts and on the other, pump the clean air taken from outside into the tunnels. The excavation areas and tunnels were also compartmentalized and separated from the rest of the construction site.
To minimize the risk of pollution, decontamination areas dedicated to both personnel and vehicles were also provided, equipped with changing rooms, showers and air extraction systems. The construction sites were also equipped with large de-dusting units that filter asbestos. Even the tunnel water during the excavation phases, containing asbestos fibres, was pumped into treatment plants, filtered and then purified.
Our construction sites and the environment
Special attention was also paid to the composition of the construction sites themselves. The 12 large construction sites, chosen as starting points for the construction of the various sections of the work, were built with different characteristics, based on their position. In developing the line, there are metropolitan construction sites (designed to be included in an urban context, like
that of Genoa or other municipalities), crossing sites (in mountainous areas with poor accessibility and an often absent or very limited road network), lowland sites (located in large flat areas, and therefore with easy accessibility, proximity to large road infrastructures, and the availability of quarries for environmental recovery interventions). Each of these sites has been set up according to the characteristics of the location, the proximity to inhabited centres, and a respect for nature.
Universities and companies: sustainability for managing excavated materials
A sustainability commitment was also made in managing excavated materials. All excavated material was subject to checks, and analysed to verify that it met the requirements set to safeguard human health and the environment.
For this purpose, Milan’s IRCSS “Mario Negri”, Turin’s Polytechnic and the University of Genoa were also involved, to develop ecotoxicological studies to determine the threshold values, below which the excavated material can be reused for TBM materials and check the presence of asbestos, with their own labs.
The material produced by TBM excavations was, in particular, first laid on the ground, at a special 150,000 m2 deposit. The latter was set up in an area near the “Romanellotta” quarry. The material was then piled up, with piles reaching one metre in height. It was also constantly turned over to guarantee the right oxygenation. Each pile was subject to chemical analysis by the Department of Chemistry of the University of Genoa. Once the treatment was completed, it was then transferred to the final sites: i.e. former quarries that are re-filled and re-naturalized, returning them to their original agricultural and naturalistic destination.
Advantages and benefits of the work
Reduction of travel times
Passengers expected per year
Co2 emissions avoided per year
Webuild: Terzo Valico dei Giovi
#break2 Valico Tunnel and Serravalle Tunnel
Terzo Valico dei Giovi Project
Genoa Junction: Serravalle Tunnel Breakthrough
Serravalle Tunnel Breakthrough