Recently Completed Tunnels
Asia and Europe are now united below sea level, thanks to the Eurasia Tunnel. This new road tunnel connects Asia to Europe, thereby reducing the heavy traffic that has always been a feature of this route. The tunnel is 14.6 km long, 5.4 km of which run right beneath the sea bed, and has two separate levels, one for each direction of traffic. It is a highly complex feat of engineering that has taken 55 months to build and an overall investment of 1 billion 300 million dollars. The excavations began on the Asian side of the Bosphorus Strait and finished on the European side. The project has also included reorganising traffic circulation. This has meant improving the access roads to the tunnel and creating two toll plazas. These changes have cut the level of traffic in İstanbul enormously and improved the quality of the local environment by reducing both atmospheric and acoustic pollution. In addition to the immense achievement of its engineering, the project also stands out for the extremely high quality of its design.
Gebze-Orhangazi-İzmir (Including İzmit Bay Crossing and Connection Roads) Motorway Project is 426 km in length which 384 km of motorway and 42 km connection road. The longest motorway tunnel in Turkey, Orhangazi Tunnel (double tube x 3.590 m = 7.180 m) belonging to this project and located on provincial border of Bursa and Yalova has been put into service in 2016.
(İZMİR-URLA-ÇEŞME MOTORWAY İKİZTEPE-KONAK-DOĞANLAR SECTION)
İzmir’s heavy urban traffic problem was solved by the Konak Tunnel connected to Mustafa Kemalpaşa Boulevard over Mürselpaşa Boulevard. The two-lane double tube Konak Tunnel has a length of 2.524 m including 1.674 m tunnel and 850 m connection roads.
RİVA AND ÇAMLIK TUNNELS
The Riva and Çamlık Tunnels are located on the Northern Marmara Motorway Third Bosphorus Bridge route in İstanbul. The four-lane double tube Çamlık Tunnel is the widest tunnel in Turkey and Europe. Tunnels were excavated by NATM.
The Cankurtaran Tunnel is a road tunnel located in Artvin Province as part of the Hopa-Borçka Highway D.010 in northeastern Turkey. Situated on the Mount Cankurtaran of Pontic Mountains between Çavuşlu village of Hopa district in the west and Çifteköprü village of Borçka district in the east, it is a 5.228 m -long twin-tube tunnel carrying two lanes of traffic in each direction. It was built to bypass the Cankurtaran Pass at 690 m elevation with many hairpin turns and to alleviate Black Sea Region’s access to Eastern Anatolia Region and consequently to Middle Eastern countries. The tunnel also eliminates the traffic burden that emerges from climatic conditions such as heavy snow fall, icing and fog. It shortens the route about 12 km. The tunnel was opened to traffic on March 1, 2018.
The Ovit Highway Tunnel project is located between İkizdere, Rize Province and İspir, Erzurum Province in Turkey. The mined section of the tunnel is approximately 12,6 km long. At the western end of the tunnel an approximately 1,4 km long avalanche tunnel, with the same cross section is added. The tunnel becomes one of the longest tunnel of Turkey with the length of 14 km. The Ovit Tunnel opened to traffic in 2018.
ILGAZ 15 JULY INDEPENDENCE TUNNEL
Ilgaz 15 July Independence Tunnel is a highway tunnel through the Ilgaz Mountains between Kastamonu and Çankırı Provinces in northern Turkey. The tunnel has twin tubes of 5.370 m and 5.391 m in length and the entrance and exit of the tunnel is designed as “shark mouth”. It is aimed at providing faster and safer transportation on Ilgaz Mountain especially during winter months. With the tunnel, the length of the Ilgaz Mountain Road, which was 16,8 km, is shortened by 5,4 km and decreased to 11,4 km.
The 4.070 m long double tube Sabuncubeli Tunnel is connecting the cities of İzmir and Manisa. It was opened on June 11, 2018.
Çamlıca Tunnels Project consists of 3 single tube tunnels and is located in İstanbul. The total length of tunnels are 3,18 km. It has been planned within the scope of highway transportation projects of Çamlıca Mosque, which is under construction at Çamlıca Hill, Istanbul. The tunnels and the mosque are opened.
MAVİ IRRIGATION AND DRINKING WATER TUNNEL
With the Mavi Tunnel, the waters of the Göksu River will be transferred to Konya Plain for irrigation. The city will also receive 50 years of drinking water. The tunnel is 17.000 m long and has 4,88 m excavation diameter and 4,2 m inner diameter.
GEREDE WATER TRANSMISSION TUNNEL
The Gerede Water Transmission Tunnel in central Turkey has been designated a national priority due to chronic drought conditions in the capital Ankara. The water supply line is 31,6 km long and draws water from the Gerede River. It is the longest water tunnel in Turkey.
The Gerede Water Transmission Tunnel is arguably one of the most difficult projects attempted in the world of tunnelling.
Turkey is in a tectonically active region controlled on a grand scale by the collision of the Arabian Plate and the Eurasian Plate. At a more detailed level, a large piece of continental crust almost the size of Turkey, called the Anatolian block, is being squeezed to the west. The block is bounded to the north by the North Anatolian Fault and to the south-east by the East Anatolian fault. Geology in the fault zones tends to be highly variable and unstable.
At Gerede, the Anatolian Fault Zone certainly presented many obstacles. Geologic testing and borehole samples showed a mix of volcanic rock including tuff, basalt, and breccia, giving way to sedimentary formations like sandstone, shale, and limestone, all punctuated by fault zones that contained clay and alluvium. The Crossover machine also faced an aquifer system that caused high-pressure water inrushes of 26 bar.