Triangeln - Malmö's new centre
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Nothern entrance
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Southern entrance
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Pillar tunnel |
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Lateral excavation |
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Final shape of the rock chamber
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Ground water system
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Triangeln station will be important for the people of Skåne and Denmark, as well as for long-distance visitors and, not least, the 23,000 residents of the area. There are theatres, concert halls, cinemas, sports arenas, shops, department stores and shopping malls within walking distance. There are also some 18,000 workplaces in the immediate vicinity of the future station.
When Citytunneln is complete, an estimated 37,000 people will pass through Malmö’s new centre every day.
The station is strategically located. The northern exit at St Johannes church leads directly out towards the Triangeln shopping centre, and the southern section of Malmö’s commercial centre. The southern exit leads towards the Faculty of Dentistry, the bus stop at Södervärn, the University Hospital (MAS), and the Möllevången-area.
Underground chamber
The station is built in an underground rock chamber with two tracks and an intermediate platform. The rock chamber at about 25 meters below ground is 28 meters wide and 12 meters high. The platform with its two tracks is 250 meters long and 14.5 meters wide. The roof of the station hall is some 5 meters above the platform. The two exits, with escalators and lifts, are located at the ends of the rock chamber.
Method
To build Triangeln Station, two vertical shafts were excavated in the northern and southern sections of the work area. But before the work of excavating the rock cavern could began, the shaft walls were strengthened with concrete sections. In order to stabilize the shaft walls, bracing consisting of strong steel tubes was assembled between the concrete sections. A total of 30 braces were placed in both shafts.
From the two vertical shafts, the rock chamber was cut out vertically and longitudinally. This was done with a roadheader, a machine equipped with a rotary cutting head on a telescopic arm. The work was carried out in stages and started with a central tunnel. When this was complete, two side tunnels were cut. Various strengthening works were carried out gradually.
The work then proceeded with the concrete structures that gave the rock chamber its final form and appearance. Finally the platforms, tracks, stairs, lift and other technical equipment was installed.
When the 25 m shafts at St Johannes church and Smedjegatan were dug, about 50,000 m3 of earth and limestone were removed. When the cavern was excavated, a further 60,000 m3 of limestone was taken out. In total, 110,000 m3 was excavated from Triangeln.
Ground water lowering
The ground water level had to be lowered during the construction period. This was done through a number of extraction wells from which water was pumped out of the rock nearest the construction shaft. The water was then pumped back into the rock some distance away through infiltration wells. This limits the area affected by the lowered water table.