He who lives quietly lives well, they say. And the FBC consortium, which is responsible for excavating the tunnel trench for the Fehmarn tunnel and inland on Lolland, has not made much of an appearance on the outside. But beneath the surface, something has happened to that extent in the last few years.
No party under the sea
Under the sea in the Fehmarn Belt, an 18-kilometer trench has now been excavated. In places, the trench is up to 40 meters deep and 100 meters wide. In construction projects on land, the first rafters are marked with a party, but you can’t eat sausages and drink draft beer in a trench under the sea, so this milestone is passed without special markings.
“The world’s best Dutch”
However, Pedro da Silva Jørgensen, who is technical deputy director of the developer Femern A/S, finds the big superlatives when he has to describe the achievement:
– We simply have the world’s best Dutch people for this. There are perhaps four or five in the world who can solve such a task, and we have had two of them here (FBC is a consortium between the two Dutch companies Boskalis and Van Oord, ed.), says Pedro da Silva Jørgensen.
Precise within an A4 sheet
From the start, high demands have been made from the client to the contractor:
– The greater accuracy you have from the start, the easier it will be later in the project. And the less consumption and construction that is needed. And we have made quite high demands. We have also learned from that, because it is of course difficult for the contractor to prove that the trench is precise within the size of an A4 sheet. But they have delivered that, says Pedro da Silva Jørgensen.
Giant rocks and clay seabed
The task has not been easy for FBC, says the technical deputy director from the client, and along the way there have also been surprises that have caused some bumps in the road:
– The hard clay seabed close to Lolland has been hard on the material, so there have been some shipyard visits. And then there were more and bigger stones down there than we had expected. Along the way, for example, an 80-ton stone appeared, and it is therefore difficult to get such a stone up, says Pedro da Silva Jørgensen.
Minor deviation from the schedule
These minor bumps in the road have also meant that the excavation work has taken slightly longer than planned. However, the deviation in relation to the schedule is minimal and within the acceptable range, says Pedro da Silva Jørgensen.
– With such large projects, it is always easiest to adhere to the schedule from the start of the project. The further the project goes, the greater the possible fluctuations. You never know what will turn up when you start digging, he says.
Has developed special solutions
During the excavation work, there has also been a need to invent special solutions and tools for the work. For example, FBC has developed and produced a special “broom”, which in principle works in the same way as a farmer’s harrow. Only “just” 40 meters below the sea.
Solutions have also been developed to limit noise under the sea in connection with the work so as not to disturb and stress marine mammals such as porpoises and seals.
Makes Lolland three square kilometers bigger
Although the tunnel channel has now been excavated, there is still something to look forward to for FBC. Four out of ten “pits” for the special elements still need to be excavated, and the final work on land reclamation on Lolland is also still pending. When the work is finished, Lolland will have become three square kilometers larger and thus moved up to 500 meters closer to Germany.
