30 October 2020

Tideway super sewer dig clears Tower bridge

Tunnel boring machine (TBM) Ursula passed underneath Tower Bridge, London, UK, this week, marking the last passage under the 21st bridge over the Thames with 19km of tunnel now constructed.

A tunnel segment being manoeuvred into place
A tunnel segment being manoeuvred into place © Tideway

The 25km ‘super sewer’, which will clean up the sewage that currently enters the River Thames, has had its outer tunnel shell built underneath west and central London and will soon start its final phase of digging in the east.

Once the outer shell is in place, the team then line its concrete segments with an inner layer of concrete, in a process called secondary lining. Tideway has named all of its machines after empowering women from London’s history Ursula is named after the British cryobiologist Dr Audrey ‘Ursula’ Smith.