Turkey’s hardest Rock: The Bahce–Nurdag High Speed Railway Tunnel

Quelle/credit: Robbins

The 8 m diameter Robbins Single Shield TBM for Turkey’s Bahce–Nurdag High Speed Railway has encountered rock up to 327 MPa UCS

Quelle/credit: Robbins

Table 1: Compressive strength of the rocks in the tunnel route

Table 2: Tensile strength of the rocks in the tunnel route

Quelle/credit: Bilgin

A constant cross-section disc cutter with a tip width of 1.2 cm and a ring diameter of 13 inches (330 mm) was used in the laboratory rock cutting experiments

Quelle/credit: Bilgin

Table 3: TBM recommended and actual parameters

Quelle/credit: Robbins

The TBM can be sealed off with closure doors against water inflow (blue) inside the muck chamber

Quelle/credit: Robbins

Onsite First Time Assembly of the Single Shield TBM

Quelle/credit: Robbins

Monthly advance rates in meters (2017–2018)

Quelle/credit: Robbins

Southeastern Turkey’s Gaziantep province is characterized by complex fractured rock within the Eastern Anatolian Fault, and it is now the location of an important railway tunnel project. With a population of nearly 1.7 million, the province is overhauling its public transportation with a rail line between the towns of Bahçe and Nurdağı. The Bahce–Nurdag Railway Tunnel consists of two parallel 9.75 km tunnels being excavated by both the New Austrian Tunnelling Method/NATM (850 m) and tunnel boring machine/TBM (8.9 km).

Contractor Intekar Yapi Turizm Elektrik Insaat San. ve Tic. Ltd. Sti chose a Robbins Single Shield TBM, 8 m in diameter (Fig. 1), to excavate one section of tunnel. Mixed ground conditions prevail on the project, and range from abrasive, interbedded sandstone and mudstone with quartzite veins to highly weathered shale and dolomitic limestone. The TBM has thus far encountered some of the hardest rock ever tunneled in Turkey, measuring between 136 and 327 MPa UCS.