Turkey’s tough Geology: The Genesis of today’s Crossover TBMs at Kargı

Quelle/credit: Robbins

Ready for startup: the TBM for the Kargı Hydroelectric project

Quelle/credit: Robbins

The 9,84 m diameter Double Shield TBM was launched in 2012 from a jobsite in mountainous Central Turkey near Ankara

Quelle/credit: Robbins

The original geological report called for softer ground for the first 2,5 km, followed by 9.3 km of unlined tunnel in competent rock

Quelle/credit: Robbins

By the time the project was 50 % complete, the geology was recognized as vastly different from the initial expectations. Multiple fault zones and collapsing ground resulted in seven bypass tunnels within the first 2 km. The entirety of the TBM-driven tunnel required segmental lining

Quelle/credit: Robbins

The crew injected micro-cement into the face in an attempt to consolidate running ground

Quelle/credit: Robbins

A custom-built canopy drill and positioner were added to the machine to allow for pipe tube installation through the forward shield

Quelle/credit: Robbins

Kargı motor and cutterhead 2-speed curve: the graph shows both standard and high torque, low speed gears. After increased torque and canopy drills were installed, the TBM traversed several stretches of severe convergent ground without becoming trapped

Quelle/credit: Robbins

Final breakthrough of the Kargı machine occurred on July 5, 2014

Quelle/credit: Robbins

The diagram shows the canopy tube spacing to stabilize ground above the Kargı TBM; the TEP II drill is similar in design and operation

Quelle/credit: Robbins

Driven through a mountainside with 600 m of cover in Central Turkey, the Kargı Kızılırmak Hydroelectric Project is one of the most challenging tunneling projects ever completed in the region. The project is located on the Kızılırmak River, near the Beypazarı district of Ankara province in Turkey.

The Kızılırmak – Turkish for “Red River” – is the longest river in Turkey. The project includes a 13 m high, 450 m wide earth dam with a concrete spillway in the southern end and a water intake construction on the northern side. The dam creates an artificial lake with a high water head of 405 m above sea level. A 11.8 km headrace tunnel diverts the water from the dam to the powerhouse situated east of the village of Maksutlu. The water from the powerhouse will flow into the Boyabat reservoir at 330 m above sea level. Once online, the project will generate 470 GWh of power annually for project...