Progress continues swiftly on London’s Tideway sewer tunnel. The first of two great shutters which is going to be used to form the secondary lining has been lowered to the bottom of the 53m-deep shaft at Kirtling Street.
Kirtling Street is located at the central point of the 25km-long sewer from where TBMs have tunneled west and east.
As the shutters each weigh approx. 240t and their length is 34m, they are being split into four sections to boost the lowering operation. They will then be reassembled to start their work by supporting the insitu-poured 250mm-thick secondary lining against the tunnel’s concrete segmental rings.
The cast secondary lining will decrease the inside diameter of the tunnel to 7.3m but supply a low-friction, smooth and abrasion-resistant surface to help gain the 120-year design life of the tunnel. Sewage will not entail pumping, but will flow eastwards under gravity along the tunnel.
The shutters are going to be used for the 5km expansion of tunnel between the work sites at Carnwath Road and Kirtling Street. A tunnel boring machine has completed the excavation of this section in November 2019.
Source: Tunnels and Tunneling
What is your reaction?