The Gotthard Base Tunnel will be inaugurated 1 June, and its breakthrough 15 October 2010 was due to Leica Geosystems surveying and monitoring systems. The 57-kilometre long tunnel is the longest and deepest rail tunnel in the world.
At the tunnel site, the surveying consortium VI-GBT started measuring in 1996. The surveying engineers set up a basic network with 20 reference points. For this task, they used Leica Geosystems total stations, optical measuring devices and GPS, or satellite navigation solutions.
Measuring down to the millimetre
During tunnel construction, surveying and measuring tasks had to be repeated every 400 metres. In order to make sure the tunnel was precisely on course, the surveyors had to check coordinates of the reference points. Also the exact height needed measuring with levelling devices – also from Leica Geosystems.
“When we broke through in the middle of the tunnel on October 15, 2010, the two tunnel sections met with a deviation of only 8 centimetres – 25 centimetres would have been tolerated,” said Ivo Schaetti, a surveying engineer of VI-GBT. “Happily, we could always rely on the accuracy of the surveying solutions from Leica Geosystems,” Schaetti adds.
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