We interview Yassine BEN DHAOUI, Deputy Director of the S2IP consortium led by setec tpi


Can you explain the Lyon-Turin project to us?

The Lyon-Turin project is a rail link across the Alps between France and Italy. It is the longest tunnel project in the world, at 57.5 km. It is divided into several operational worksites (lots), with setec tpi acting as project management agent for 2 operational worksites covering around 25 km.
The project involves a lot of excavation, so there is a real environmental issue at stake. To reduce the project’s footprint as much as possible, we have set ourselves a very ambitious target for the re-use of this excavated material.

To achieve this, we have designed the project around a circular economy: the materials come out of the depths of the mountain, are transported by conveyor belt, sorted, stored, processed, crushed and then reused to make concrete.

We have a clear objective of reuse: 15 to 20% of materials from the mountains should be reused in the manufacture of concrete. Another objective is to reuse at least 50% of these excavated volumes in landscaping, in backfill, which is quality landscaping for work on other lots of the TELT project and even for other municipalities. The rest will be used to fill in old quarries.

What benefits will the project bring to passengers and freight?

The Maurienne valley is heavily congested by transport. Italy is a major supplier to Europe (steel, agriculture, etc.).
The idea of this project is to transfer a large amount of road traffic to rail, which would reduce the region’s carbon footprint. What’s more, the Mont Blanc and Fréjus tunnels will be relieved of a great deal of traffic by the opening of this line, which will bring a real plus in terms of road safety.
As far as passengers are concerned, the journey between Lyon and Turin will take less than 2 hours compared with more than 4 hours before the works, which is significant for connecting major European cities.

What is setec’s role in this project?

We are the consortium leader on this project. The technical aspects were divided up in the design phase, with setec‘s role covering:

  • Project management by setec tpi ;
  • The management of excavation materials, their reuse, the design of new concrete formulas, etc., managed by the lerm ;
  • The design of new calculation methods with a new approach to the installation of retaining walls and the phasing of excavation, managed by terrasol;
  • setec Opency is carrying out an Operations Management mission with setec organisation as well as a General Attendances management mission on the Saint-Jean de Maurienne base.

Of course, we were involved in the design of all the other aspects: tunnel boring machine, safety equipment, planning, etc. We also have a role in coordinating the interface between the various lots, as well as steering the group internally to ensure that all partners were working in the same direction.

What companies has the setec group teamed up with?

To successfully complete this project, we are partners on the complete management missions, with Systra on the French side, Italferr on the Italian side, and PINI, a Swiss company with considerable expertise in tunnels with very large coverage.

What are the challenges?

The major issues in this project are linked to the environment for the client and the region. Hence the very high standards required to protect flora and fauna, and to respect local residents. In particular, the water sources to which we attach great importance by setting up very detailed monitoring of underground water inflows and springs in order to make the necessary correlations and deploy all the necessary measures to neutralise the slightest impact on the associated ecosystems. Finally, there are of course issues of time and cost, to ensure that commitments to Europe, the principal funder, are met, (funded 40% by the European Union, 35% by Italy and 25% by France).

What does this project promise for the setec Group?

This is a project so rich and diversified that it brings a real capitalisation of know-how in several fields but also challenges innovation in various sectors, namely :

  • We are currently working with the lerm on a performance-based test protocol for a XA3+ concrete, concrete resistant to an aggressive environment higher than XA3, which does not exist in current standards. It’s a collaborative effort involving all those involved in the project, i.e. the contractor, the client and the project manager, as well as external laboratories. lerm‘s expertise is essential, and they are working closely with us on this project.
  • Another innovation launched on this project is the waterproofing of very deep underground structures. CETU is working with a number of manufacturers on a performance-based protocol to ensure the supply of waterproofing membranes that are sufficiently sized to withstand the mechanical stresses to which these tunnels with their heavy cover are exposed.

All of this is an asset for the setec group. It also opens up European markets for us, such as Switzerland and Austria, which are more advanced in these areas than France.