Record Chinese TBM holes through in Moscow

27 July 2021

Chinese crews have holed through in Moscow using the largest-diameter shield TBM ever exported by China to Europe.

The 10.88mØ TBM (‘Victory’) had finished mining a 2.677km-stretch of the eastern section of Moscow Metro’s Big Circle Line. China Railway Construction Corp (CRCC) said it had designed the machine to operate in the Russian winter, in temperatures as low as –30°C.

According to CRCC, the best monthly performance was 433.8m, thanks to an ‘optimised construction mode’. The company added that no settlement was measured during the TBM’s passage under the Kolomenskoye Estate, a series of delicate 15th century former royal wooden buildings in south Moscow; this was partially aided by the use of rubber-wheeled locomotives to transport segments for the tunnel lining and which effectively avoided the risk of slippage mishaps caused by excessive gradients.

Various measures were used on site to protect workers from Covid-19, including twice-daily body temperature checks; enhanced tunnel ventilation and disinfection; and regular nucleic acid testing to ensure the health and safety of all staff.

With a total length of 70km when completed, the Big Circle Line (BCL) will be the world’s longest circular line and have 31 stations. It will link present and proposed radial lines and is situated 10km out from the city’s existing circle line. BCL was originally scheduled for completion in late 2022 although this may not now be achievable given the disruption caused by the pandemic.