Wednesday, May 21

The Laerdal Tunnel, World's longest tunnel

The Lærdal Tunnel was built during a five-year period from 1995-2000 at a cost of approximately 125 million U.S. dollars. It is an important link in the ferry-free road connection between the Bergen area and Eastern Norway, including Oslo, and is especially significant for winter traffic, when the high mountain passes are closed, or subject to closing, because of snow. The mountains above the tunnel reach elevations up to 1809 meters (5935 feet), and the breathtaking high-mountain road between Aurland and Lærdal, the so-called Snow Road, is open only for a few months during the summer. This tunnel is not only the world's longest, 24.5 km ( 15.2 miles), but also the world's most uniquely constructed tunnel with exceptional security features. (The world's second longest, the St. Gottard Tunnel in Switzerland, is only 16.92 km, or 10 miles). An access tunnel of 2.1 km (1.3 miles) was built from a side valley, Tynjadalen (Tønjum Valley), 6 km (3.72 miles) from the Lærdal side. This enabled the crews to drill from four sites, which shortened the construction time. This access tunnel also serves as an extraction tunnel for the ventilation system, and made it possible to deposit the excavated rock on the Lærdal side in an environmentally secure area.

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