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The Gotthard base tunnel

some history of Leica Geosystems
With systems for surveying and monitoring the drilling is completed without problems of a long tunnel 57 kilometers, starting from the two sides of the mountain to meet in the middle, with detection of slight deviations.
To obtain this result, highly accurate measuring tools were needed to guide operations and lead to the completion of the project.
The measures have been tested with up to millimeter precision.
The tunnel work was started in 1996, 20 years ago. The engineers of mailed surveys a basic network with 20 reference points. For this task, they used total stations, optical measuring devices and GPS satellite navigation solutions from Leica Geosystems.
Drilling began, not only in Erstfeld (north portal) and Bodio (south portal), but also in three intermediate points where the side channels have reached the main tunnel Amsteg, Sedrun and Faido. In Sedrun (1,405 m high), a vertical 800 m long tunnel was drilled into the main gallery so that construction workers can go both north as well as south from that point. During the construction of the tunnel, the pads and the various measuring tasks were to be repeated every 400 meters.
In order to make sure that the tunnel was positioned right on the course of the project, inspectors had to check the coordinates of the reference points. Moreover, the exact height must be measured with leveling system also by Leica Geosystems.
At the time of breaking the last wall in the middle of the tunnel, October 15, 2010, the two tunnel sections have met with a deviation of only 8 cm, compared with the maximum design tolerance assumed at 25, "said Ivo Schaetti , an engineer for the relief of the VI-GBT.
He explains that the tunnel detection is very demanding because of temperature changes, moisture and dust. "Fortunately, we could always rely on the accuracy of the Leica Geosystems' detection solutions, adds Schaetti. "I am very precise. It is possible to measure a distance of 400 meters with an accuracy of less than a millimeter."
E 'was performed anchr monitoring of dams above the tunnel during the entire period of construction, the surroundings of three artificial lakes above the tunnel required monitoring: Curnera, Nalps and Santa Maria. There was a slight chance that the construction of the tunnel, positioned at a depth of 1.4 kilometers beneath the lakes, he could affect the stability of their dams. The fully automated devices from Leica Geosystems have monitored dams throughout the entire construction of the tunnel from 2000 until 2015.
"Our total stations have been monitoring the slightest movements of the prisms that were mounted in the vicinity of the dams," says Falko Henning, Leica Geosystems product manager. "Fortunately, no unusual movement occurred."
There was no major delay during the construction time, and the tunnel will be inaugurated as planned l '1 June 2016.
On 1 June 2016, 17 years after the first explosion in the main tunnel, the longest railway tunnel in the world will be officially inaugurated. Switzerland has a good reason to celebrate.
A Swiss tradition
Leica Geosystems has a rich history in Switzerland. From its origins with Kern & Company founded in 1819 in Aarau, leader today in the field of measurement technology, global operations serving customers in many segments, including engineering, construction, and mining. Leica Geosystems has a tradition of nearly 200 years, with a commitment to the Swiss and global vision quality, supports since then professionals worldwide to achieve feats of engineering like this tunnel.
With systems for surveying and monitoring the drilling is completed without problems of a long tunnel 57 kilometers, starting from the two sides of the mountain to meet in the middle, with detection of slight deviations.

To obtain this result, highly accurate measuring tools were needed to guide operations and lead to the completion of the project.
The measures have been tested with up to millimeter precision.The tunnel work was started in 1996, 20 years ago. The engineers of mailed surveys a basic network with 20 reference points. For this task, they used total stations, optical measuring devices and GPS satellite navigation solutions from Leica Geosystems.

Drilling began, not only in Erstfeld (north portal) and Bodio (south portal), but also in three intermediate points where the side channels have reached the main tunnel Amsteg, Sedrun and Faido. In Sedrun (1,405 m high), a vertical 800 m long tunnel was drilled into the main gallery so that construction workers can go both north as well as south from that point. During the construction of the tunnel, the pads and the various measuring tasks were to be repeated every 400 meters.
In order to make sure that the tunnel was positioned right on the course of the project, inspectors had to check the coordinates of the reference points. Moreover, the exact height must be measured with leveling system also by Leica Geosystems.

At the time of breaking the last wall in the middle of the tunnel, October 15, 2010, the two tunnel sections have met with a deviation of only 8 cm, compared with the maximum design tolerance assumed at 25, "said Ivo Schaetti , an engineer for the relief of the VI-GBT.
He explains that the tunnel detection is very demanding because of temperature changes, moisture and dust. "Fortunately, we could always rely on the accuracy of the Leica Geosystems' detection solutions, adds Schaetti. "I am very precise. It is possible to measure a distance of 400 meters with an accuracy of less than a millimeter."

E 'was performed anchr monitoring of dams above the tunnel during the entire period of construction, the surroundings of three artificial lakes above the tunnel required monitoring: Curnera, Nalps and Santa Maria. There was a slight chance that the construction of the tunnel, positioned at a depth of 1.4 kilometers beneath the lakes, he could affect the stability of their dams. The fully automated devices from Leica Geosystems have monitored dams throughout the entire construction of the tunnel from 2000 until 2015.

"Our total stations have been monitoring the slightest movements of the prisms that were mounted in the vicinity of the dams," says Falko Henning, Leica Geosystems product manager. "Fortunately, no unusual movement occurred."

There was no major delay during the construction time, and the tunnel will be inaugurated as planned l '1 June 2016.
On 1 June 2016, 17 years after the first explosion in the main tunnel, the longest railway tunnel in the world will be officially inaugurated. Switzerland has a good reason to celebrate.

Leica Geosystems has a rich history in Switzerland. From its origins with Kern & Company founded in 1819 in Aarau, leader today in the field of measurement technology, global operations serving customers in many segments, including engineering, construction, and mining. Leica Geosystems has a tradition of nearly 200 years, with a commitment to the Swiss and global vision quality, supports since then professionals worldwide to achieve feats of engineering like this tunnel.

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