Terre Armée offers engineered solutions for tunnels and underground structure applications.

Buried concrete arches and box tunnels

For more than 30 years, our teams have designed and furnished precast concrete arch tunnels for different types of sectors and clients. Our TechSpan® and TechBox™ solutions allow for a predictable and economic means for constructing underground tunnels. Our solutions deliver a very competitive alternative for the construction of cut and fill tunnels and underpasses, and are often used efficiently in combination with Terre Armée retaining walls.

Building underground transport tunnels

Most urban areas are experiencing a continual increase in population density and land scarcity for the development of above-ground transport infrastructure for railways, roadways and pedestrian pathways. With traffic subsequently becoming denser and urban infrastructure development becoming more complex, engineers are challenged to find ways to build these passageways underground.

Terre Armée precast arches and box structures address these challenges. For these structures that require excavating and forming through landforms and pre-built infrastructure, our precast arches and boxes for underground tunnels are an excellent solution.

Building underground industrial and utility tunnels

Reclaim and conveyance tunnels have long been considered as critical structures facilitating mining and manufacturing operations while ensuring safety for the workers on site. Precast arch tunnels have proven to be an excellent solution for the construction of material reclaim and conveyance tunnels and utility and pipeline enclosure tunnels.

Emergency escape tunnels

Safety norms require the construction of galleries when tunnels are built underground, allowing for emergency escape for workers, for instance in the event of a fire. Very resistant to fire and extreme temperature variations, TechSpan® precast concrete arches and TechBox™ precast concrete boxes can be used to meet these highest safety standards.

Design value and global expertise

Finite Element Method (FEM) design is used by our engineers to accurately calculate the optimal radius of curvature of the arch to minimize tensile stresses for the creation of a highly durable and resilient, axially compressed structure. Through FEM analysis, concrete and reinforcement volumes are optimized to result in the most cost-effective solution.

At Terre Armée, our teams have designed and furnished materials for buried tunnels for major rail, road, industrial, military and energy projects since 1989 in more than 30 countries.

Related solutions



Resulting from decades of research and development, TechSpan® is a buried precast concrete arch system designed to accommodate high fills, heavy live loads, and alternating loading conditions. With a small footprint and easy and quick to install, TechSpan® is ideal for mining, industrial, and railway applications, it is gaining popularity in many different markets. See the many uses of our precast arch system.



TechBox™ consists of precast box elements used to build a structure under backfill. It allows rapid on-site regulated installation. The soil cover required in TechBox™ structures is lower than for arch structures.

Reinforced Earth®

Reinforced Earth®

Our flagship technique, Reinforced Earth®, is based on the principle of the friction between soil and reinforcements creating a permanent and predictable bond. At the origin of all mechanically stabilized earth (MSE) walls on the market today, we are continuously perfecting this ingenious technique.

Do you have a project? Fill in the form to contact our experts…

* Mandatory fields

Share this page !