Greece Drives Metro Advances

摘要

Metro tunnelling work in Greece is shifting focus with the final breakthrough on the Line 2 extension in Athens metro and main excavation getting underway on the Thessaloniki subway. Completion of Line 2 tunnelling was marked by hole through last month at Aghios Dimitros station, which saw the 5.5km long single tube, double-track extension tie-in to the existing network after 4.6km of boring. A refurbished and adapted Herrenknecht shield was employed on the drive and operated by Seli, which is in the JV subcontractor with Aegek, Aktor and J&P-Avax. Main contractor is a JV of Aktor, Vinci and Siemens. The developer is Attiko Metro. Geology comprised soft to medium soft strata, including river deposits, sandy clay, schist and some limestone at the end. The shield was run in EPB mode at depths of 15m-30m, placing 1.5m long rings of 9.18m o.d. and 350mm thickness, and progress was up to 15m per day. However, archaeological finds have delayed completion of the overall project by some months to early 2010 (T&TI, October 2008, p8).