The breakthrough of a Robbins Crossover XRE tunnel boring machines were the cause of many celebrations in October 2021. A team of personnel from Turkish State Railways (TCDD), Kolin Construction, and Robbins field service have met to observe the breakthrough of the world’s fastest tunnel boring machine over 13 m (43 ft) in diameter.
The 13.77 m (45.18 ft) XRE machine has set the world’s records three times over, beating its own records in May and June with a set of records over the summer, containing the best day of 32.4 m (106 ft), the best week of 178.2 m (584.6 ft), and the best month of 721.8 m (2,368 ft). The machine which has been launched in March 2021, mined 3.05 km (1.90 mi) on the Esme-Salihli Railway Tunnel as part of the Ankara-İzmir High-Speed Railway Project for the TCDD.
Onur Kansu, TBM Manager of project contractor Kolin Construction stated: “When the strength, force, and torque generated by our Crossover TBM are taken into account, we consider it to be a beast. It has performed extremely well in this tunnel.”
“We are proud we have accomplished such high performance,” added Kansu.
The TBM started its excavation in altered gneiss, after, passed through mélange including gneiss, sandstone, claystone, mudstone, quartz, and silt. At the end of the excavation, the TBM was mining in mainly mudstone. Every 200 m before boring, core drillings were taken so the crew felt confident with the geology—just one of several factors that were into the record rates.
Kansu continued: “A proper geological analysis, choosing the right TBM, a professional crew, and a contractor who believes that they can break records are all key.”
He also mentioned: “Scheduled maintenance periods, an expert team, availability of sufficient spare parts, and good logistics also made it possible for us to reach our targeted advance rates.”
Particularly, the project is significant for the Turkish tunneling industry, showing what is possible at larger tunnel boring machine diameters.
In addition, Kansu specified: “We have disproved the idea that it is difficult to reach high advance rates while boring in EPB mode with large diameter TBMs. Crossover TBMs enable us to find quick solutions in changing ground, so we believe they will be the preference for future projects.”
Once the tunnel boring is completed, work will keep up on the 508 km (316 mi) line that is going to link Polatlı in Ankara Province to Izmir, the third most populous city in Turkey.
After the completion, the Ankara-İzmir High-Speed Railway is going to be the longest rail line in the country, transporting the passengers at the highest speeds of 250 km/h (160 mph) in a railway trip of nearly 3.5 hours.
To find out more about this TBM please visit Robbins’ website.