Tunnel through Hallandsas moving – New Technology

     Tunnel through Hallandsas will open in 2015. Right now installation. Photo: ULF Angberg
     

Professor Roland Pusch has long warned of the risk that the rail tunnel Hallandsas becomes unstable. Now measurements show that the western tunnel has moved a few millimeters.

Levelling measurements at nine points in Mölleback zone, the most thorny part of the tunnel, shows that the tunnel has moved up, then down in the autumn of 2013. At most, one point moved three millimeters.

Then for four weeks at the turn of the year 2013/2014 are no measurements for the route.

– There was a glitch in communication with the contractor. A team’s task was to clear everything in the tunnel and then cleaned, they also remove these measurement points, says Kenneth Rosell, Transport Administration’s project manager for the tunnel construction.

The new measuring points were added up and the measurements during the spring of 2014 showed that the points that most moved just under two millimeters.

Because the measurement series is not continuous, it is impossible to say how much each point has moved a total of over time, but the maximum tunnel would have been able to move five millimeters in the period.

I think Kenneth Rosell at the transport department is a little.

– It is still stable. It requires a number of inches, I would say, before anything would be alarming, he said.

He also pointed out that the movement arose while the contractor Skanska-Vinci grouted in cement mortar around the filling, the space between the rock and the so-called lining, which forms the tunnel tube.

– It is no wonder it moves then. It injects the pressure and takes one side at a time, it is too easy to get some movement in the rings, he said.

But Roland Pusch, adjunct professor of geotechnical engineering at Luleå University, disagrees.

– The movement shows that the lining has no stable position. It rests on something which is deformable and has something about him which is deformable, and the movements will be duplicated when the heavy traffic going on, he said.

He thinks that the Swedish Transport Administration’s view that the underground movements is not alarming until they cover a number of centimeters is” just ate the pepper. “

– With the heavy rail services, there is today a millimeter to get centimeters. Then massage the lining elements that lead to deformations and water will come out to the track bed becomes waterlogged and trains threaten to derail, he said.

In a report on Shim says contractor Skanska-Vinci that no significant movement has been measured after grouting was completed in January 2014. The Transport Agency also believes that other measurements, such as exploratory drilling, confirms that the tunnel is stable.

But Roland Pusch is convinced that the tunnel through Hallandsas is unstable and find that the speed of the trains should be lowered to about 70 km / h to reduce forces the tunnel.

– But then the whole point of Hallandsås Tunnel gone, he says.

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