Seli strides in Athens, set for Thessaloniki

Seli has just had another intermediate breakthrough on the Line 2 extension to the Athens metro and is set to add to its project workload in Greece with the first of two EPBM and backups due to be dispatched to Thessaloniki metro.

The 9.46m diameter refurbished and adapted Herrenknecht TBM being operated by Seli holed through at Argyroupoli station on Athens metro last month, having recently achieved average progress of nine rings, or 14m, per day. The best advance in a day for the excavated diameter of 9.5m was 14 rings, the best week 67 rings. The 9.18m o.d. segmental (7+1) ring is 1.5m long and 350mm thick.

A JV of Aktor, Vinci and Siemens is building the 5.5km long single bore extension to Line 2 for client Attiko Metro, the tunnelling works having been subcontracted to a JV formed by Aegek, Aktor, J&P-Avax and Seli.

Tunnelling works are 4.6km long, started in February and having previously passed Elliniko station the machine will continue north to Alimos and Ilioupoli stations, and then join the existing Line 2. Works on the link are due to complete in September 2008 for the extension to be commissioned late 2009. Seli previously worked on the metro, in 2001-3, on the Line 3 eastward extension.

The same client is also building the metro in Thessaloniki, which unlike Athens calls for excavation of twin bore, single track tunnels, each 7.7km long. Seli is supplying the backup to the twin 6.12m diameter Herrenknecht EPBMs.

Geology along the route consists of clay, sandy clay, and sand with cover up to 28m deep. While some stretches of ground are very weak, the principal challenge is driving below historic buildings. The 5.3 i.d. precast concrete, five-piece bolted segmental ring will be 300mm thick. Seli said a key feature includes a customer-tailored two-component grouting system.

The 15m launch shaft is under construction near New Railway Station, and assembly of the first EPBM is due to start early 2008. Shifts are being limited initially by the station construction schedule. The first drive will be 2.5km long to the Sintrivani crossover, passing stations at Dimokratias, Venizelou and Agia Sofia.

Seli and lead contractor in the JV, Aegek, will do the tunnelling works under a subcontract priced at approx. US$99.5M. Works are due to be completed in 33 months, and the entire link with 13 stations is to be opened by mid-2010.

Other members of the JV contractor are Impregilo, Ansaldo Trasporti and Ansaldo Breda – the latter having done a similar driverless metro in Copehangen.

JVs involving Seli have made further advances on Athens metro Line 2 Breakthrough on Athens Metro, Line 2 A JV involving Seli are set to begin boring next year on the first line being built in Thessaloniki Thessaloniki's TBM