Terratec has announced the successful delivery of two earth pressure balance tunnel boring machines (TBMs) for Istanbul’s new Halkali airport metro connection project.
The Halkali-Yeni Havalimani Metro joint venture, formed by Cengiz İnşaat, Kalyon and Kolin, will use the TBMs to drive the new 31km line for the Turkish Ministry of Transport and Infrastructure.
The new line will feature six stations and connect the Halkali with Istanbul’s recently opened third international airport.
The TBMs have versatile mixed-face dome-style cutterheads that have proven to work extremely effectively in Istanbul’s mixed geology with seven other Terratec TBMs working on other parts of the city’s 335km metro expansion project. Ground conditions expected to be encountered on the airport link include sandstones, siltstones, limestones and volcanic rock.