Building underground mobility

  • Vue en profondeur d'un tunnel routier moderne et vide. Les murs sont blancs, le plafond est noir, et la chaussée grise présente des lignes blanches avec des silhouettes d'arbres noires éclairées le long des parois supérieures.

    35 years of tunnel expertise

    We have over 35 years of experience of designing and delivering road and rail tunnels on every continent.

  • Vue aérienne d'un grand chantier de construction urbain avec une fosse circulaire profonde, une grue portique verte et une grue mobile jaune. Un tramway circule à côté, avec une rivière et des bâtiments urbains en arrière-plan sous un ciel clair.

    Innovation in action

    Giant tunnel boring machines, robotics and digital technologies are at the core of solutions that enhance safety and optimise performance on every site.

Our expertise

  • Une excavation massive révèle deux grandes entrées de tunnel sombres en construction, encadrées par des murs de béton brut, des échafaudages rouillés et des bannières Dragages Hong Kong. Des tuyaux jaunes proéminents traversent la scène, avec une structure métallique rouillée et des barrières de sécurité rouges et blanches au premier plan, sous un ciel bleu vif.

    Solutions tailored to every use case

    From the earliest engineering studies, we propose routes and construction solutions adapted to any geological or urban constraint.

    The extension of the RER E regional rapid transit line in Paris demonstrates this expertise, with technical and operational parameters related to the route anticipated right from the design stage.

  • Une tête de tunnelier massive est assemblée dans un chantier souterrain, entourée de travailleurs, de structures métalliques jaunes et de conduits de ventilation lumineux.

    A full range of excavation techniques

    We use the full range of excavation methods. Our highly experienced teams adapt their methods to each geological and environmental context, ensuring safety and performance on every project.

    For the NorthConnex project in Australia, we used advanced rock-cutting machinery, including roadheaders and robot‑equipped tools, suited to sandstone ground.

  • Tunnel routier moderne et lumineux, éclairé principalement en bleu avec des silhouettes d'arbres stylisées sur la droite et des reflets jaunes sur la gauche, tandis qu'une route vide à deux voies s'y courbe.

    Guaranteed safety and optimised operations

    We deliver turnkey tunnels incorporating all essential systems, including ventilation, signalling, fire protection, video surveillance and water management.

    We installed a wide range of innovative safety and traffic management systems on the Marseille L2 ring road project, for example.

  • Des ouvriers en gilets orange sur une machine de chantier avec un tambour rotatif soulèvent du ballast et de la terre, tandis qu'un train bleu et gris passe à toute vitesse dans un tunnel éclairé.

    Refurbishing and adapting existing tunnels

    We carry out major renovation and redimensioning works on existing tunnels. We provide technical solutions to extend the service life of infrastructure.

    The Fréjus Tunnel has been renovated to meet updated European standards and enhance traffic safety.

  • Deux ouvriers en tenues de sécurité orange travaillent sur des voies ferrées à l'intérieur d'un tunnel sombre aux murs de briques, éclairés par de puissantes lampes de travail.

    Ensuring infrastructure longevity

    Our knowledge of operational infrastructure, combined with our ability to work on live sites, allows us to provide an integrated service for inspection, repair or reinforcement of structures.

    For example, we reinforced the Simplon Tunnel, which has been in service since 1906, to continue connecting Switzerland and Italy.

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Expertise in different excavation techniques

We specialise in all tunnel construction methods and adjust our solutions to suit a wide range of geological, urban, and environmental contexts.

  • Tunnel boring: slurry‑shield, earth‑pressure, mixed‑shield or multi‑mode tunnel‑boring machines (TBMs). They demonstrate our pioneering ability to design and adapt high‑precision equipment to a wide variety of geological contexts.
  • Traditional methods: blasting and targeted excavation, supported by shotcrete and rock bolts. Our expertise is built on extensive experience, ensuring reliable solutions even in the most challenging geological conditions.
  • Immersed tunnels: prefabricated caissons, towed and assembled underwater. This method requires special expertise in design and the coordination of waterborne operations, where innovation and careful planning are key to finding the best solutions.
  • Hyperbaric excavation: our teams are trained for work under pressure, essential for underwater or deep‑sea projects. This specialised expertise ensures operational safety and the continuity of excavation even in the most challenging environments. In Hong Kong, our teams excavated the Tuen Mun-Chek Lap Kok Tunnel at depths of up to 50 metres below sea level in a high‑pressure environment.
Un ouvrier en combinaison orange et casque de sécurité se tient sur des rails à l'intérieur d'un long tunnel souterrain aux murs bétonnés, teinté de vert par l'éclairage, regardant vers une lumière éclatante au loin.

Robotics and Digitalization for Greater Safety and Performance

The expertise of our technical and equipment teams translates into a unique ability to design, adapt, and deploy innovative solutions for tunnel boring.

  • Robotics: Our teams develop robots to make underground work safer and easier. The Telemach robot enables the maintenance of cutting heads in hyperbaric environments, while Roby 850 automates the installation of anchors and reduces the need for human intervention on job sites, such as on the NorthConnex project in Australia. These innovations reduce risks for operators, improve the ergonomics of tasks, and ensure increased productivity with higher-quality execution.
  • Digitalization: We integrate digital technology to optimize tunnel design and construction. The Thalia simulator trains operators in virtual reality, and the “Operator’s Eye” collects and analyzes data in real time to improve tunnel boring machine performance. These innovations enhance safety, reduce delays, and improve construction quality. We also develop digital tools for predictive maintenance, capable of anticipating equipment wear and optimizing maintenance interventions to ensure maximum availability of the tunnel boring machines.
Entrée d'un tunnel autoroutier moderne sous un ciel bleu clair, avec des murs gris ornés de silhouettes d'oiseaux sur la gauche et de rayures verticales jaunes et blanches sur la droite, surmontés d'un grand panneau d'affichage électronique.
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