Breakthrough at theEurasia Tunnel –“Welcome to Europe”
In the afternoon of August 22, 2015 a Herrenknecht Mixshield with an excavation diameter of 13.7 m pierced the target shaft wall of the Eurasia Tunnel on Istanbul’s European side exactly to plan. The invited guests, with Turkish Prime Minister Ahmet Davutoğlu among them, witnessed the finale of an exceptional construction achievement. After 16 months of tunnelling under the Bosphorus Strait, the emergence of the drilling giant was a significant success for the building contractors, Turkish-South Korean joint venture Yapı Merkezi as leader and SK Engineering & Construction: Never before has such a large tunnel been built underground under such complex and extreme conditions.
Tunnelling at a Water Pressure of 11 bar
The mission to implement the 3.34 km long underpass for the two-story Eurasia road tunnel was launched on April 19, 2014.The 3300 tonne tunnel boring machine with a length of 120 m had been specially designed in Schwanau and started in Haydarpaşa on the Asian side of Istanbul at the south-eastern end of the Bosphorus. With a gradient of five percent the large-format Mixshield tunneled down to the deepest point 106 m below the Bosphorus. There the water pressure was 11 bar. Combined with a very changeable, wear-intensive underground, this placed extreme...