Tunnelling activity in the Nordic countries is running high, with an array of projects under way or planned. These range from an underground coal storage project in Helsinki, the Copenhagen metro, the Stockholm Southern link road project, tunnels for the Botnia Rail Line in northern Sweden, a number of tunnelling projects on the E18 Oslo to Stavanger highway, and a road tunnel in the Faeroe Islands.
Finland and Denmark
Excavation work has begun on the coal store in Helsinki beneath the Salmisaari power plant.
At present coal for the plant is stored at ground level near the seashore at Ruoholahti, a few kilometres from the centre of Helsinki, in an area with many office blocks. On completion, the underground store will be able to hold 250,000t of coal, freeing the cleared site for office buildings, a marina and sports facilities. The contract period is for two years.
The client for the work is Helsinki Energy; the main designer is Kalliosuunnittelu Oy Rockplan and the main contractor is Hiili, a joint venture between Lemminkäinen Construction and YIT Corporation. The cost will be around US$42.7m (FIM300m). A total of 550,000m³ of rock will be excavated.
In addition to this work is a 185,000m³ extension of the Viikinmäki underground wastewater treatment plant plus several road tunnels on Highway 1 motorway between Helsinki and Turku. A long railway tunnel for the planned Vuosaari harbour in Helsinki is also being studied.
A preliminary design has been drawn up to extend the Helsinki metro to Espoo. There are also a number of underground car parking caverns, under way or planned, in different city centres in Finland.
A US$800M driverless metro is being built in the centre of Copenhagen. The first 11km phase, being constructed by an international consortium, is scheduled for completion next year. Phase two is due for completion in 2003; a third phase has yet to be confirmed.
In the Faeroe Islands, Swedish contractor NCC is building a 5km long tunnel under the Vestmannasund Straits. The Vagar Tunnel, worth US$16.4m (SKr180m), will be the islands’ longest tunnel as well as the region’s first underwater tube, at 10.5m wide and 105m below sea level. It will connect the islands’ airport on Vagar, with the capital Thorshavn on the island of Streymoy.
Spotlight in Sweden
On the other side of the Øresund channel from Denmark, in Sweden several major projects are in the spotlight.
The government has now decided, in principle, to complete the Hallandsås Tunnel. Construction of the 8.6km twin tube tunnel was stopped in October 1997 after groundwater contamination was discovered from chemicals from the sealant being used to reduce the water leakage into the tunnel. Around a third of the tunnel has been completed at a cost of US$182M (SKr2,000M). The client, Banverket, estimates it will now take around eight years to complete the tunnel at a cost of $364-409M (SKr4,000-4,500M).
More promising is the Malmö City Rail Tunnel project, the final link for rail traffic across the Øresund fixed link on the Swedish side. Construction of the City Tunnel is planned to begin in 2003 and finish in 2008. An application for permission to construct is now with the Swedish government.
A rail tunnel has also been proposed between the Swedish city of Helsinborg and the Danish town of Elsinore but no decision has yet been taken.
In the north of the country a major rail project, the Botnia Rail Line, is progressing (see News). The $745m (SKr8.2bn) line will be 190km long and include 25km of tunnel. The Kalldal Tunnel was completed in May this year by Lemminkäinen Construction, which is now pushing ahead on the 480m long Öberget tunnel. Meanwhile, AF Spesialprosjekt, a subsidiary of the Norwegian contractor AF Gruppen ASA, is working on the 1,250m long Hjälta Tunnel. Both are due to be finished in February 2002 with the line opening in 2008.
On a smaller scale is the tram tunnel now under construction in Gothenburg. The 1,050m long twin-tube rock tunnel will be completed this autumn, as part of the Gothenburg Agreement, a package of investments in transport communications in this area. The largest road project in the Gothenburg Agreement is the 1.5km long Göta Road Tunnel, part of the 3km long Götaleden with a project value of more than $182m (SKr2,000m). Work began in November last year for completion in autumn 2005.
Construction is divided into a number of contracts, the main ones being concrete tunnels, 150m and 350m long, at each end of the road tunnel, and the 1km long central rock tunnel.
Stockholm has its own investment programme in traffic links. Its Southern Link motorway is at an advanced stage of construction, part of a planned ring road around the city and comprising 16.6km of rock tunnels and 2M.m³ of excavated rock. Construction work began in 1998 and 95% of the blasting work is now finished. The whole project will be complete and open to traffic in 2004.
The Northern Link section of the Stockholm ring road has still to receive the go-ahead from local and national politicians, and the Swedish National Road Administration estimates it may be four years before construction can start.
Norwegian schemes
In Norway major road tunnelling schemes are a key part of the upgrading of the E18 between Oslo and the Norwegian oil capital Stavanger. Works are spread through the Norwegian National Road Administration’s districts of Vestfold, Agder and Rogaland. In Vestfold, 11 tunnels are under construction, about 20% of the overall route. The longest tunnels are Hanekleiva at 1,765m, and 1,100m for Knattåsen and Stuåsen. All are twin tube, with a height of 4.8m and are due for completion in September 2001.
Other E18 projects are the Baneheia Tunnel in Kristiansand and the Bragernes Tunnel in Drammen.
Major tunnels such as the Laerdal and the Bomlafjord road tunnels opened for traffic last year. Among those planned is the Oddernes road tunnel in Kristiansand, while a new double track rail line between Oslo and the western suburb of Asker will be mostly in tunnel.
Iceland’s 12-year plan
In Iceland, a 12-year construction plan for road tunnels was adopted by parliament in spring 2000. Tenders for the first two will be awarded this winter for a 2002 start. Schemes earmarked include a 5.3km long tunnel on the island’s east coast and two tunnels totalling 11km in length to the north.
A final decision on the building of a hydropower station planned for the north east of Iceland, which will include a 32km long tunnel is expected to be made early in 2002. Its construction is linked to the building of an aluminium plant that will be the main purchaser of the electricity.
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