World Tunnel Congress 2017: Tunnelling in Norway
High mountains, long fjords and steep valleys. A demanding landscape and tough climate with abundant precipitation meaning infrastructure construction is a severe challenge in Norway, host of the World Tunnel Congress 2017 from June 9 to June 15 in Bergen.
The especially demanding circumstances became all the more obvious as roads and railways started to replace the sea routes as the standard means of travel in Norway. The first Norwegian road tunnel was built in 1884. The great breakthrough for traffic tunnelling came with the construction of the Bergen Railway in 1909: 182 tunnels were constructed as part of this first rail connection between east and west of Norway. Today Norway has more than 1800 road and rail tunnels, whose total length is well over 1000 km.
Norway is a major supplier in the renewable energy network thanks to the high number of hydroelectric power plants. Many hydroelectric projects in the second half of the 20th century formed the industrialized Norway. Today some 6000 km of tunnels serve the 200 hydropower houses underground. The demand for more green energy is sought-after all over the world and Norway has this expertise.
Norwegian Tunnelling Technology
Drill and blast tunnelling was the main method when constructing the many hydroelectric projects in the 20th century, remaining the common way of tunnel excavation in Norway. Experienced tunnellers assess how to support the tunnel in consultation with engineering geologists at face. Computer aided drilling jumbos use digitally defined drilling patterns and a drill log for on-site analysis. Geological mapping, measuring leakage rates, permeability and rock quality all help determine whether pre-grouting of the rock is required.
TBMs have assisted in Norway’s extensive hydropower projects, where international manufacturers were challenged to develop suitable machines for the hard and abrasive Norwegian rock. About 260 km of hydroelectric power tunnels have been excavated with TBM. Within the next few years, TBM will be used for both railway and hydropower projects.
Future pioneering Projects
Stad Ship Tunnel – construction of the world’s first ship tunnel may commence in 2018. With a section of 1620 m2 and length of 1.7 km, it will offer safe passage through a notoriously exposed piece of coast with many ship accidents
Solbakk Tunnel – as a part of the Ryfast connection- the world’s longest subsea road tunnel will be 14.3 km long when completed in 2018
The Helgeland Tunnel, the world’s deepest road tunnel is being planned to descend 396 m below sea level – more than 100 m below any other road tunnel in the world today
When it opens for traffic in 2023, Rogfast Road Link in Rogaland will become the world’s longest sub-sea road tunnel at 27 km, and among the world’s deepest at 390 m
The Follo double-tube Railway tunnel will be Norway’s longest rail tunnel when completed in 2021. Most of the 20 km tunnels will be excavated by TBMs.
In 1963 the Norwegian Tunnelling Society (NFF) was established. The membership of more than 1100 individuals spans the entire scope of the profession – from project owners, to contractors, consulting engineers, equipment suppliers and research centres. NFF is actively involved in the international aspects of the profession, and contributed to the formation of the International Tunnelling Association (ITA) in 1974.