Mammoet has lowered a 690-ton (625.9-tonne) tunnel boring machine (TBM) for the Thames Tideway project in London.

Challenges included being situated in a highly congested and compact site. Mammoet planned a tailor-made solution to fit within the restricted dimensions while managing the limited ground bearing pressures.

Maurice Janssen, project manager, explained: “We removed the risk of [delays] through a series detailed plans. The key equipment was pre-tested at our yard in Schiedam before it began its journey to London, to ensure there would be no unexpected problems on site.”

He added: “Given the populous surroundings, the project had to be completed within an acoustic shed; a metal structure designed to minimize noise pollution.”

Mammoet mobilised and built the handling system in three weeks. The TBM was then lowered down a 35 m shaft with just 25 cm of clearance over the course of one ten-hour shift, ensuring drilling could start on schedule.

Thames Tideway – also known as London’s ‘super sewer’ – is an ambitious infrastructure project that comprises the construction of a 25 km-long network of tunnels beneath the city.

Mammoet has also been contracted to lower two additional TBMs for the final phase of the project.