Ruins uncovered at Monastiraki compare with other key sites of ancient Athens, on and around the Acropolis. Ministry of Culture investigations therefore delayed work for an extended period. A 2,000-year-old aqueduct still carrying water will be permanently on show from a window in a now redesigned station entrance.
The station is in the middle of the tourist area, surrounded by buildings including two very old churches and a mosque, as well as the 90-year-old station for Line One. Access is through one shaft 15m by 21m and 29m deep.
The station is also in extremely difficult ground, which one engineer described as being "like mud". Attiko manager of projects John Dickson says it is the "worst I have ever seen".
To cope, the station design uses a longitudinal arch of interlocking concrete-filled steel pipes for its main space. Smet Tunnelling pipejacked behind two Herrenknecht 1,250mm diameter microtunnelling shields in 1997.
But cancellation of the next station along, at Keramikos, because of even greater archaeological finds means Monastiraki becomes the temporary terminal station for Line Three. The 100m ‘umbrella’ must be extended 26m towards Syntagma and 8m in the other direction.
This is under way now using NATM "with just about every method you can think of" says site manager for Attiko Metro Ioannis Karakitsios. Top heading is almost completed and two bench sequences will follow.
Meanwhile, a 460m long twin track tunnel connection to Syntagma is being excavated under a separate contract, also using NATM. The top heading broke through on 9 March. Sections of parallel single track running on 150m into the station are included plus another 260m on the far side, with a final triple track section of 194m for a turnaround area at the end.
The contractor is a joint venture of Aegek, Meton and Domika Erga.
