Strains in sprayed concrete tunnel linings at Heathrow Terminal 4

Eur Ing Dr Benoît Jones is speaking at The Institution of Civil Engineers on Wednesday 4 November, as part of the Geotechnical Engineering Proceedings Lecture. It's a biennial address nominated by the Editorial Panel of ICE Proceedings Geotechnical Engineering, so it's a bit of a flagship slot for the geotechnical community.

Jones's talk, Strains in sprayed concrete tunnel linings at Heathrow Terminal 4, draws on nearly 20 years of monitoring data from strain gauges embedded in the sprayed concrete lining of the concourse tunnel at Heathrow Terminal 4 station. He'll be talking through how stresses were back-calculated from those measured strains using the rate of flow method, and how that was compared with pressure-cell readings at the same locations. The data reveals a 20-year history: compressive strain increased up to about three years and then decreased slightly over the following 15 to 16 years. Jones's hypothesis is that this trend comes from radial groundwater flow through the primary lining, followed by the gradual application of hydrostatic water pressure to the waterproof membrane and secondary lining.

Jones is a Chartered Civil Engineer and the author of the textbook Soft Ground Tunnel Design. He's picked up a few awards along the way, too: the 2022 NCE Tunnelling Award, the ICE Telford Premium Award in 2009, and the ICE Crampton Prize this year. If you're into tunnelling or ground engineering, he's a name you've likely come across.

The session runs from 18:30 to 20:30 at One Great George Street, Westminster, SW1P 3AA, and it's webcast live if you can't make it in person. There's a drinks reception afterwards, sponsored by AtkinsRéalis, and entry is free.