Breakthrough on Phase 1 of Budapest’s Line 4 metro

Global News

Both Herrenknecht EPB TBMs mining Phase 1 of the US$1 billion Line 4 of the Budapest metro have broken through at the strategic Keleti station, thereby completing the two running tunnels for the Phase 1 stretch of line from Kelenfold to Keleti.

Phase 1 comprises two 7.3km long bores each of 5.2m internal diameter that have been excavated by TBM. The stretch will include ten stations and will intersect with existing metro lines 2 and 3, as well as the main railway network.

Tunnels have been constructed with between 15-20m ground cover. The geology of the (Phase 1) alignment for the first 4.2km from Kelefold to the river Danube comprises tertiary sediments (mainly clay) on the Buda side. On crossing the Danube, a major fault zone is encountered on the Pest side, after which mainly tertiary sediments prevail.
NATM has been used to construct the 14 cross-passages between the two running tunnels; and also for three ventilation shafts and a 140m3 cross-section cross-over structure at Gellert station.

International engineering consultancy Mott MacDonald has served on the design team and also completed the detailed design for the sprayed concrete lined (SCL) tunnel at Bocskai Street Station. The company also provided advice on settlement, SCL design and the underpassing of the river Danube.

The US$250 million contract for the design and construction of Phase 1 was awarded in January 2006 to the Bamco consortium comprising Vinci Construction Grands Projets, Strabag AG, Strabag International, Strabag Zrt and Hidepito Zrt.