[11/20/2006]
Tunnel boring begins
Work has started on cutting the Citytunnel. One of the project’s two tunnel-boring machines has now begun work in the Holma shaft.
‘I’m very pleased that we’ve come so far with the project and that we’re keeping to schedule’, says Örjan Larsson, Citytunneln Project Manager. ‘Preparation work and assembly of the machinery have gone very well’.
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Örjan Larsson, Citytunneln Project Manager. |
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Heike Rottman, shift engineer, MCG underground section inside the TBM. |
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Control cabin. |
The first months are a running-in period in which the boring machines work relatively slowly while adjustment and trimming take place. It is also a running-in period for the team of workers who have to handle the machines.
‘Tunnel-boring is a very complicated and advanced technology. The man-machine relationship also has to be set up. Also, the organisation around these machines must be frictionless’, says Örjan Larsson.
At the Holma site, a track has been laid for the trains that will serve the tunnel borers. It will bring up tunnel lining segments and work material for the machines and will also transport personnel.
The most intensive tunnelling work takes place within the 10-m steel shield. It is here, for example, that the prefabricated concrete segments are assembled to form the tunnel lining. Behind the shield there is a 110-m service unit with essential functions such as power supply, water, ventilation, workshops, office, and personnel space. A long conveyor belt carries excavated material back through the machine and out of the tunnel to a depot in Holma. From there, it is taken by truck to the North harbour. At full power, up to 100 m3 of rock cuttings per hour will be removed from the tunnel.
In about a few months it is estimated that the machine will be up to its normal work rate of 12-15 metres of tunnel per day. Generally, tunnelling will go on 24 hours a day in two bore shifts and one service shift. About 15 persons per shift will be employed on each machine.
In general, the Citytunnel project is running on time, and the first tunnelling machine has started drilling slightly ahead of schedule. In about a month it will be time for the second machine to begin drilling.
‘It feels safe to be a bit ahead of schedule’, says Örjan Larsson. ‘We have prepared very well but it’s a complex project and we could find ourselves up against unforeseen difficulties later on’.
According to the plans, the tunnel borers will have reached the station building at Triangeln by the autumn of 2007, and got as far as Malmö C before the turn of 2008/2009.
The Citytunnel in Malmö consists of 17 km of railway connecting Malmö Central Station with the Öresund Bridge, as well as linking up the Scania railway network and increasing rail traffic capacity for the future. Six km passes underneath central Malmö, and the other 11 km is surface railway.
Malmö Central Station is being extended with an underground section. New stations are being built at Triangeln and Hyllie.
The first spit was dug on 8 March 2005. The Citytunnel is planned to be complete in 2011. The budget for the project is SEK 9.45 billion at 2001 values.