New EPBMs to launch from Istanbul metro mid-point 05 Mar 2020

Gulermak, Nurol & Makyol JV is currently completing TBM testing on-site for the new Ümraniye-Ataşehir-Göztepe (UAG) line, the latest addition to Istanbul’s metro expansion.

New 6.56m diameter EPBMs

There are already nine Terratec TBMs working on the metro system in Istanbul,Turkey. Four further machines - Terratec 6.56m diameter EPBMs - are due to join these and be operational from mid-May. Two are being tested on site and the other two are already assembled and waiting for the launch, which will be from Finans Merkezi Station, the mid-point of the line.

The 13km-long Ümraniye-Ataşehir-Göztepe (UAG) line, along with its 11 new stations and NATM-built connections, will form a second north to south rail corridor under the densely populated Anatolian side of Istanbul and will be located entirely underground at an average depth of about 30m.

The Terratec TBMs have versatile mixed-face dome-style cutterheads with an opening ratio of about 35% that have proven to work extremely effectively in Istanbul’s mixed geology – which includes low-strength sandstones, siltstones, limestones and shales – as well as other state-of-the-art features such as VFD electric cutterhead drives, tungsten carbide soft ground cutting tools that are interchangeable with 17in roller disc cutters, high torque screw conveyors and active articulation systems.

As the four TBMs progress north and south on a 24hr basis, they will install 1.5m wide by 30cm thick pre-cast concrete lining rings, which consist of five segments plus a key. Mucking will be via continuous conveyor with TBM and materials supply provided with the use of Multi-Service Vehicles (MSVs).

Istanbul Metro expansion routes

The Ümraniye-Ataşehir-Göztepe (UAG) project is one of one of a number new metro lines currently being built in the city that will increase the current 145km metro network to more than 480km. Members of the JV were so impressed with the performance of the Terratec machine used on the Mecidiyeköy-Mahmutbey Metro, which is being built by the Gulermak, Kolin & Kalyon Joint Venture – and the progress of two other 6.56m diameter EPBMs that were delivered in 2017 to the Şenbay Madencilik-Kolin-Kalyon Joint Venture for the Dudullu-Bostancı Metro Line – that they were keen to employ a further four Terratec machines on this latest project.

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

Elsewhere in the city, four 6.56m diameter EPBMs are also making good progress for the Halkali-Yeni Havalimani Metro JV (consisting of Cengiz İnşaat, Kalyon and Kolin) on the Halkali-Istanbul New Airport metro line, which was awarded to a consortium comprising Özgün Yapı and Kolin by the Turkish Ministry of Transport and Infrastructure (AYGM).

The 31km-long line, along with six new stations and connections, will form the western-leg of the new M11 Line that runs from the recently opened third International Airport on the European side of the city southwards to Halkali (which will also be the final terminus of the new Marmaray railway). On the other leg of the new M11 line (the 37km-long Gayrettepe-New Airport metro line that is being constructed by the Kolin-Şenbay consortium), a refurbished Terratec machine put in a solid performance on its section of the project last year, achieving a best day of 33 rings (46m). It is now being prepped for its third project in the city.