Underwater laying of topotubes, experimental site
A slope protection experiment was undertaken at the Bagger lake using our top tubes. As a result, a shallow water zone could be created. In the experiments, the topotubes were prepared on a pontoon and discharged into the water.
Different technical possibilities were researched to reach even greater depths. The resulting concepts could be protected by patents.
The experiments show that there are different potential application scenarios for the incorporation of topotubes under water.
- erosion protection
- Scour protection
- Slope protection
- land reclamation
The two application scenarios listed below have been examined in more detail.
When a embankments begins to slip, it is not uncommon that in ends in a break the embankment. Only an adequate securing of the embankment can prevent this. The depositing of large quantities of sand is often not suitable, since they have hardly any stability and can still slip away.
For embankment protection, topotubes are laid at the foot of the embankment.The tubes are filled with available soil material, such as sand.If the resultant abutment is successfully established, the upper embankment area can be filled with further material.This takes place from the embankment foot.
Kolk- and erosion protection for foundations
The foundation of offshore windmills is an example of collapse and erosion phenomena. After setting up the windmills, they form a natural obstacle to ocean currents. For example, soil wells can be flushed out at the foundation, which can reach a depth of up to seven meters. These scour present a risk to the static of the overall structure. In order to prevent the formation of scour, rocks, stones or geotextile containers are often distributed around the base of the structure as a stabilisation of the seabed. Topotubes may provide an advantage in positioning accuracy and sagging stability. Due to the fact that the tubes are connected with less joints it offers a greater resistance to the flow. By covering the seabed, they develop the same protection against erosion phenomena as geotextile sand containers. The flexible form of both the geotextile container and the geotextile tubes can also be seen as an advantage over a stone bed.
Effective protection against scour - and erosion can also be achieved in other cases, such as river flows or other water structures that become exposed to water flow.