
Tunnels
Tunnels
Building underground mobility

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

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

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.

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.

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.

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.

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.

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.

Our projects

Central Tunnel of Central Kowloon Route
Creation by Bouygues Travaux Publics and Dragages Hong Kong of an underground road link in the heart of Hong Kong, on the Kowloon Peninsula.

Channel Tunnel
The teams’ involvement in the construction of the tunnel, a 50-kilometre undersea rail link between France and the United Kingdom.

Fréjus railway tunnel
Bouygues Travaux Publics modernized and upgraded 7 km of the Fréjus rail tunnel to European gauge standards, a key link between France and Italy.

North East Link
6.5 km tunnel in Melbourne with diaphragm walls and deep foundations, ensuring structural stability and performance.

NorthConnex tunnel
A key backbone of northern Sydney mobility, NorthConnex improves travel, safety and links between the north and west.

Simplon Tunnel
Connecting Switzerland and Italy, the Simplon Tunnel is one of the longest railway structures in the world, at nearly 20 kilometers.
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Tuen Mun-Chek Lap Kok Link
Hong Kong’s deepest, longest and largest sub-sea road tunnel.