Protecting the River Thames from sewage pollution
A special issue of the Proceedings of the Institution of Civil Engineers – Civil Engineering has been released.
This issue is dedicated to the Thames Tideway Tunnel, a major infrastructure project designed to protect the River Thames from sewage pollution. The 25 km tunnel is now operational and has already intercepted over nine million tonnes of storm sewage, preventing it from entering the river.
View issueOne featured paper, Thames Tideway Tunnel: TBM Performance in the London Clay Formation and Overcoming Man-Made Obstructions, by Tim Newman, Dominic Molyneux, and Rosar Soler Pujol, examines the western-most section of the tunnel (Main Tunnel A) between Acton Storm Tanks and Carnwath Road Riverside. This 7 km section has an internal diameter of 6.5 m and lies at depths ranging from 30 m to 42 m, connecting to three CSO drop shafts.
Construction employed an earth pressure balance tunnel boring machine (TBM) to excavate entirely within the London Clay Formation. Detailed ground investigations and shaft construction enabled accurate geological modeling and identification of faults. While the TBM’s performance was unaffected by these variations, it faced significant challenges when intersecting two existing boreholes. Contingency measures included adjusting TBM operating parameters and increasing both in-tunnel and surface settlement monitoring to ensure structural integrity.
You can explore the tunnel’s geology, construction techniques and the engineering solutions that overcame these challenges.
Read the full articleDominic Molyneux brings over 35 years of UK and international experience in dam engineering and underground works, including major hydroelectric schemes. He is a member of the All Reservoirs Panel of Engineers, licensed by the UK government to ensure public safety under the Reservoirs Act (1975).