GNSS to assist construction on tunnel from Germany and Denmark

When completed, the underwater auto and rail tunnel will connect Germany and Denmark. (Image: Femern A/S)

A European megaproject is relying on GNSS to guide supportive earthworks during construction. The Fehmarn Belt Fixed Link is a planned underwater tunnel that would allow travelers to go by car or train between Germany and Denmark in only seven to 10 minutes. Once completed, the 18-kilometer-long tunnel will be the world’s largest of its kind and is expected to employ up to 3,000 people.

The 7 billion Euro project is expected to be completed in nine years. Danish construction company Holbøll A/S is building earthworks for 56 bridges on the main route crossing Denmark to where the tunnel would start. Holbøll’s undertakings include ramps and drainage work for the new bridges.

Holbøll has 130 employees and a machine park of 22 machines equipped with machine control from Leica Geosystems, enabling it to deliver innovative and sustainable solutions on time and at the agreed price.

At one of the bridges in Vordingborg, operator Flemming Ove Nielsen uses a Leica iCON GD4 3D system on the 61PX Komatsu dozer to perform the first rough work for building the slopes. Using the the iCON GPS 80 receiver, the iCON grade iGG4 system ensures fast and reliable grading with GNSS. Nielsen uses machine control to create the slope, and then the excavator takes over for the final grading work.

Image: Femern A/S

“The dozer is very efficient for this sort of work because it can move so much dirt and, with machine control, hold the correct angle of the blade,” explained Carl-Ole Holbøll, co-owner and managing director of Holbøll. The dual GNSS solution for the dozer is an advantage because the slope is so steep, and to achieve an accurate cross-slope, dual GNSS is required.

On another bridge, an excavator is using the Leica iCON iXE3 3D system for the finishing layer of the ramp slope. The operator can document the height of the different dirt layers simply by placing the bucket and letting the iXE3 register the height. This saves time — the operator doesn’t have to wait for a surveyor to conduct as-built documentation for each layer.

The Fehmarn Belt Fixed Link prime contractor, Femern A/S, has taken the next steps to develop the area where the factory for the tunnel elements will be built. Continued archaeological surveys, preparatory supply infrastructure and drainage has been financed at 55 million Euros.

Geared with Leica Geosystems, Holbøll A/S has prequalified for several of the derived projects, including the draining and moving of eight hectares in Strandholm Lake in Denmark.