Double shield TBM begins Kargi Kizilirmak hydropower expansion
8 August 2012A 10m diameter double shield TBM, launched in central Turkey in Spring 2012, has advanced over 400m despite difficult ground including unexpected fault zones and inflows of water and mud, Robbins announced yesterday.
The excavation is part of the Kargi Kizilirmak Hyydoelectric Project, what will become of Turkey's largest hydropower stations to date.
Crews for contractor Gulermak, project wonder Statkraft and Robbins are guiding the machine through changeable geology.
The project consists on an 11.8km long headrace tunnel through a mountainside near the town of Osmancik. Ground is expected to consist of volcanic-based rock with softer limestone for the first 3km, giving way to harder geology including marble for the rest of the route. 20m daily advances are expected to be continued.
Segmental lining of the tunnel will take place for the first 3km, the remainder of the tunnel will be supported with ring beams and rock
bolts, as well as final linking of shortcrete.
"We have had some very impressive efforts by the Gulermak and Robbins teams," said Glen Maynard, Robbins Field Service Manager. "After the TBM has bored 175m with a temporary conveyor system, tunnelling was interrupted to install the permanent conveyor system. Gulermak completed this installation is six days; on day seven the Robbins Continuous Conveyor System was operational, and normal boring operation was resumed."
