KARGI HYDROELECTRIC PROJECT
KARGI HYDROELECTRIC PROJECT
Multiple fault zones, variable face conditions and squeezing ground requiring extensive bypass tunneling: These were just a few of the challenges overcome in order to successfully complete Turkey’s Kargı Kızılırmak Hydroelectric Project. A Robbins 10 m (32.8 ft) diameter Double Shield TBM achieved breakthrough on the project July 5, 2014 after an impressive run through some of the most difficult conditions ever encountered by Robbins field teams. The machine type, selected jointly by the owner, consultants, Robbins, and the contractor Gülermak of Turkey, excavated through 7.8 km (4.8 mi) of complex geological conditions that proved to be a challenge nearly from the outset.
The machine was launched into poor geology that resulted in delays to the project and forced team members to find innovative solutions that included major in-tunnel modifications to the machine. In the first 2 km (1.2 mi) of boring a total of seven bypass tunnels were needed to free the TBM from collapsed ground. The cutterhead stalled on numerous occasions as the conditions varied widely from solid rock to running ground. Small and wide faults along the alignment added another level of complexity, as the excavation was located very close to the North Anatolian fault line in Turkey’s relatively recent rock formations.
Once online the Kargı Kızılırmak Hydroelectric Project, for Norwegian-owned Statkraft AS, will generate 470 GWh annually, which is enough to power about 150,000 homes. The tunnel will source water from the Kızılırmak River, sending it to a new generating station operated by Statkraft.
