EPBMs ready for Istanbul airport metro connection 07 Feb 2019

There are now a total of nine Terratec EPBMs working on the Istanbul Metro system expansion with the latest two delivered following a successful factory acceptance test to start work on the Halkali-Istanbul New Airport metro line. Ordered by the Halkali-Yeni Havalimani Metro JV of Cengiz Insaat, Kalyon and Kolin, the two new 6.56m diameter EPBMs have mixed-face dome-style cutterheads that have proven to work effectively in the mixed geology of Istanbul that includes reaches in sandstone, siltstone, limestone and volcanic rock. The machines have VFD electric cutterhead drives, tungsten carbide soft ground cutting tools that are interchangeable with 17in disc cutters, high torque screw conveyors and active articulation systems. As they progress, the TBMs will erect the five segments and a key in each 1,500mm wide ring of 300mm thick precast concrete segmental lining.

Successful factory acceptance of EPBM

Project delivery of the Halkali-New Airport metro line was awarded to a consortium comprising Özgün Yapı and Kolin by the Turkish Ministry of Transport and Infrastructure and will comprise a 31km long line with six new stations and connections. It forms the western-leg of the new M11 Line that runs from the recently opened third international airport on the European side of Istanbul, southwards to Halkali, which is also be the final terminus of the Marmaray railway under the Bosphorus.

It is one of a number of new metro lines currently being built in the city that will increase the current 145km metro network in Istanbul to more than 480km. Members of the Cengiz Insaat, Kalyon and Kolin JV were impressed with performance of their previous Terratec machines on the Mecidiyeköy-Mahmutbey, Dudullu-Bostancı and Ümraniye-Ataşehir-Göztepe metro line contracts and decided to employ a further four new machines on the Halkali-New Airport link.

EPBM destined for Halkali-Istanbul New Airport metro line

In March 2018, one of the Dudullu-Bostancı Terratec EPBMs completed an advance of 19 rings in a single shift, equating to 28.5m of excavation in 12 hours. This was a new production record for a TBM of this size and class in Istanbul.

More recently, on the 37km-long Gayrettepe-New Airport metro line that is being constructed by the Kolin-Şenbay consortium, a refurbished Terratec machine achieved a best day of 33 rings or 46m in 24 hours.

“Terratec is excited to be providing yet more machines to metro projects in Istanbul,” said Terratec Sales and Marketing Director, Bruce Matheson. “We are confident they will perform as well as previous machines have in the city and we look forward to breaking new records for on-time delivery, quick assembly and excellent production rates.”