A 300m connection tunnel between Hammersmith Pumping Station and the middle of the River Thames will connect into the 25km Thames Tideway Tunnel has been completed.
This first fully excavated tunnel for the project is 5.1m diameter for the first 50m, then narrows down to 4m diameter.
Excavation of the tunnel started in August 2018 using mechanical excavation, one metre at a time, before a sprayed concrete lining was applied to the exposed clay using a robotic manipulator.
The sprayed concrete lining at Hammersmith is the first time a waterproof sprayed concrete has been used in the UK. According to Tideway this reduced the time spent as no waterproof membrane is required between the primary and secondary linings.
Tideway project manager Morgan Anamoah said: “Although it’s not the biggest on the project, this is the first fully excavated tunnel for the super sewer, a huge step in our work towards cleaning up the River Thames.
“Our work in Hammersmith will help stop one of the most polluting sites along the river and it is something we’re all immensely proud of.”
Hammersmith Pumping Station currently spills around 1M.t of untreated sewage into the Thames each year on average.
Hammersmith tunnel agent Ed Batty said: “The levels of production and quality have been exceptional, and that’s really down to the engineers and the miners who have shown real passion toward getting the job done.”
The new tunnel will come into operation once work is complete in 2024.