TERRATEC announced the successful site acceptance testing of two new 6.56-m diameter Earth Pressure Balance Tunnel Boring Machines (EPBMs) for the ongoing expansion of Istanbul’s Metro system, in Turkey. These EPBMs, along with another two new sister machines that have been delivered to this project, will bring the number of TERRATEC machines working on the city’s metro to a total of seven.
The new TBMs will be used by the Gulermak, Nurol & Makyol JV on the Ümraniye-Ataşehir-Göztepe Metro line, which was awarded in April 2017. The 13-km line, along with 11 new stations and NATM-built connections, will form a second north-to-south rail corridor under the densely populated Anatolian side of the city and will be located entirely underground at an average depth of about 30 m.
The robust 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 17-in. roller disc cutters, high torque screw conveyors and active articulation systems.
These machines (S65 and S66) will be launched from Finans Merkezi Station and mine towards Göztepe Station. As the TBMs progress on a 24-hr basis, they will install 1,500-mm wide by 300-mm thick precast 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).
The Ümraniye-Ataşehir-Göztepe project is one of five new metro lines currently being built by the Istanbul Metropolitan Municipality (IMM). 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 6.56-m 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.
In March 2018, one the Dudullu-Bostancı TERRATEC EPBMs completed an outstanding advance of 19 rings in a single shift (equating to 26.5 m of excavation in just 12 hours), to accomplish a new production record for a TBM of this size and class in Istanbul.
“Terratec is excited to be providing yet more machines to the metro projects in Istanbul,” says TERRATEC Sales & 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 more records for on-time delivery, quick assembly and excellent production rates.”
The new lines will increase the city’s current 145km Metro network to more than 480 km.