Novedades

"Moles" under Lausanne

The ground under the Vaud capital was rooted up by the "construction site of the century". Kilometres of tunnels have been created for the first Swiss underground and the future Tridel waste transport railway.

Five days a week, 16 hours a day, 100-tonne local section machines dug their way through the earth under Lausanne. Centimetre by centimetre, they cut the tunnels for the Lausanne underground, called the M2, and the waste transport railway which will end at the waste reprocessing plant Tridel on the edge of Lausanne. Together, these two projects have caused the greatest transformation of the city in Lausanne's history. The Tridel project alone has a volume of 360 million Swiss francs, while the underground M2 will cost 590 million francs. Although the two construction sites are located close to one another, they are completely separate. The only thing they have in common is the same time frame.

High Daily Performance

Two imposing local section machines from the company Eickhoff were in use especially for the Tridel Tunnel. One machine led the attack from the south, the other from the north. They were equipped with tool systems from Betek. The German manufacturer from Aichhalden in the Black Forest designed the tungsten carbide quality of the tool systems especially for this application, thus minimizing wear.

Initially the bits BGS 27 and BGS 75 were mounted on the machines. But in the underground area the work ran into rock with a high proportion of strongly abrasive quartz. A different Betek bit was chosen for the job, the BGS 66, and it turned out to be the ideal fitting. "The record for the day was 30 metres," according to Mr Eichelberger from BAZ Service in Horgen, the Swiss representative for Betek tool systems, "because Betek quality means long working life and makes it possible to drive forward faster."

"Like a video game"

The machines are controlled via a monitor which displays a green ball. This represents the drill head which is working through the molasses of the passageway. If the ball changes to yellow, the machinist knows that he has gone more than 2 cm astray from the roof of the future tunnel. If the colour changes to red, the deviation is more than 5 cm and the machine is outside of the tolerances. "The precision of the system made it possible to reduce significantly the excavation volume and cut costs substantially because only the tunnel size which was really required had to be dug," said the foreman of the future Saint Laurent Tunnel.

Tunnels now in the fitting phase

The tunnel excavation has now been completed for both projects and the fitting work is in full swing. Once again it has been shown how important the perfect interaction between machine, tool and task at hand is. The name Betek and its guarantee for "Progress!" stand for these seamless solutions.