Differences between open shield and closed shield tunnels

What are open shield tunnels?

Open shield tunnels are ideal for stable, cohesive ground. This method employs a metallic structure that protects the excavation process, but does not use active pressure systems to stabilize the ground. For this reason, it is mainly used in projects of low complexity, where ground conditions allow working without risk of collapse.

Advantages of the open shield:

• Simplicity in execution.
• Lower initial cost.
• Suitable for rocky or dry soils.

This method is common in rural works, such as road tunnels or small infrastructure crossings. If you would like to explore more about the equipment used in this type of project, see our section on equipment with open shield.

What are closed shield tunnels?

On the other hand, closed shield tunnels are designed to cope with difficult terrain, such as clayey, sandy or underwater soils. This method uses active pressure to stabilize the excavation face, either by means of EPB (Earth Pressure Balance) o hydro shield.

This technology is essential for projects where safety is a priority, such as urban crossings o submarine emissaries. Although its initial cost is higher, its ability to prevent landslides and guarantee stability makes it a necessary investment in complex terrain.

To learn more about the equipment specialized in this type of work, visit our section of equipment with closed shield.

Key differences between open and closed shields

Both methods excel under specific conditions, but have fundamental differences:

• TerrainThe open shield is adapted to stable soils, while the closed shield is designed for unstable or saturated soils.
• CostThe open shield is more economical due to its lower technical complexity.
• SecurityThe closed shield provides greater protection in urban or underwater projects.

A practical example is the use of enclosed shields in projects such as seawater harvestingThe use of the water in desalination plants, or crossings under rivers and in dense urban areas, is essential.

How to choose the right method?

The choice between an open or closed shield tunnel depends on factors such as the stability of the terrain, the location of the project and the available resources. For example, for an infrastructure crossing in a rural area with stable terrain, the open shield is sufficient. However, in an urban tunnel or under a body of water, the closed shield ensures the necessary safety and stability.

If you are evaluating options for a subway project, we invite you to explore our microtunneling solutions, ideal for a variety of technical applications.

Success stories and trends in tunnel construction

The evolution of tunneling technologies has made it possible to carry out complex projects all over the world. For example, the International Tunneling and Underground Space Association (ITA) highlights advances such as active pressure systems in urban terrains. In addition, publications such as Tunnel Business Magazine provide an overview of the latest trends in the sector.

These resources provide inspiration and practical knowledge to improve results on projects in the following areas tunnel construction.

In conclusion, open shield and closed shield tunnels are essential tools to overcome the challenges of subway construction. While the open shield is ideal for stable ground and simple projects, the closed shield adapts to complex conditions, ensuring safety and efficiency.

At EurohincaWe have experience in both methods and offer specialized teams to guarantee the success of your project. If you need advice or more information about our solutions, do not hesitate to contact us. contact us atWe will be happy to help you find the best technology for your site!