Immersion and underwater technology

Strukton is worldwide market leader in immersed tunnels. Strukton Immersion Projects (SImP) is the specialist company of Strukton International for the floatation, transport and immersion of tunnel elements and caissons. The scope of work of Strukton Immersion Projects includes the engineering, preparation and execution of the immersed tunnelling processes including the required marine works.

SImP specialism overview


Thanks to a law of physics, a hollow concrete tunnel segment remains afloat in water. SImP takes advantage of this law to bring the object into optimum position before it is immersed.

To ensure that once the segment has been correctly positioned it can still be immersed, its ballast tanks are filled with water until there is a predetermined amount of excess weight. This makes the tunnel segment heavy enough to immerse in a controlled manner. The immersion commander uses winches to carefully lower the segment into a previously-excavated ditch. The ballast water is then replaced with ballast concrete, which ensures that the section stays in position.