Tunnel boring machine sets new world records

By Leila Steed04 August 2021

The Crossover XRE TBM from Robbins and the team from Kolin Construction

US tunnelling equipment specialist Robbins said one of its Crossover XRE tunnel boring machines (TBM) working in Turkey has set new world records for the longest daily, weekly and monthly lengths of excavated tunnel.

The Crossover XRE TBM - model number 451-379 - was deployed by contractor Kolin Construction in March 2021 to bore the new 3km Emse-Salihli Railway Tunnel in Turkey.

The 13.7m diameter machine was able to bore tunnel lengths of 25.3m (83ft) in one day, 117m (383.8 ft) in one week, and 345.6m (1,134ft) in one month.

The tunnel will form part of Turkish State Railways’ (TCDD) new Ankara-İzmir High Speed Railway project. Measuring 508km long, the double-track railway will operate between Polatlı in Ankara Province to Izmir on the country’s west coast.

The TBM broke the previous 12m (39ft) daily performance record set by another Robbins TBM in the same diameter class. The Crossover XRE TBM then went on to break its own newly-set records just a month later.

In June of 2021 the TBM achieved new daily, weekly and monthly bored tunnel lengths of 28.5m (93.5ft), 133.2m (437ft), and 455.4m (1,494ft) respectively.

Onur Kansu, TBM manager for project contractor Kolin Construction, said, “The most important reason for achieving fast advance rates is that we have an experienced and qualified team.

“Such a team allows us to anticipate the malfunctions and to go to the solution in a very short time. In addition, all necessary maintenance is carried out on time, and the appropriate consumables are selected to increase the performance.”

Specifically designed to work in ground that comprises a mixture of hard rock, soft soils and boulders, Robbins said the machine’s large diameter design enables both a screw conveyor and belt conveyor to remain in place. This allows it to operate in different modes according to the ground type and to quickly change between modes.

On the excavation of the Esme-Salihli Railway Tunnel, which is still ongoing, the Crossover XRE TBM has been boring through sandstone, gravelstone, claystone, and siltstone.