[2/15/2007 ]
Both TBMs are on their way in Malmö
Citytunneln’s second tunnel-boring machine, Katrin, has now started work on the eastern tunnel. Katrin will be cutting through the ground 25 m beneath Malmö. The first tunnel boring machine, Anna, which started work in November, has so far cleared almost 500 m.
‘I’m very satisfied so far’, says Johan Brantmark, Construction Manager, Tunnels. ‘So far the work has gone as planned and we’re running a little ahead of schedule’.
Tunnel boring machine (TBM) Katrin now faces a commissioning period when it will work relatively slowly while adjustment and trimming take place.
‘Cutting tunnels with TBMs is an advanced and complex technique’, explains Johan Brantmark. ‘Several months of adjustment are needed to make sure that everything runs properly. This involves not only the machine, but also working methods and the organisation behind the tunnel-boring process.
In a few months, the machine should have reached its normal work rate of around 12-15 m of tunnel per day on average. Generally, tunnelling goes on twenty-four hours a day in two drilling shifts and one service shift. Each shift employs about 15 persons per machine.
TBM Anna, which is cutting the western tunnel, has reached almost 500 m. The first two months’ work has gone according to plan. A couple of longer planned stops have been made to allow adjustment of the cutter head.
‘The experience from Anna’s first phase will be valuable now that Katrin has started’, says Johan Brantmark. ‘We’ve now obtained important knowledge of the geology and of the machine, which should ease the running-in period for Katrin’.
The most intensive tunnelling work takes place within the machine’s 10-m shield, where, among other things, the precast concrete sections are assembled to form the tunnel lining. Behind the shield follows a 110-m service unit with necessary functions such as power supply, water, ventilation, workshops, office, and personnel spaces. A long conveyor belt carries the waste material back through the machine and out of the tunnel to a storage area at Holma, from which it is removed by truck to the North Harbour.
A rail system has been constructed at the Holma site for the train that will serve the tunnel-borers. The train supplies the machines with tunnel sections and working material, and also transports personnel in and out.
According to the schedule, both machines should reach Triangeln station in the autumn of 2007, and it is estimated that they will have got as far as Malmö C before the turn of the year 2008/2009.
The Citytunnel project 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, south of Malmö.
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.