Thames Retaining Wall Monitoring, Chelsea to Battersea, London, UK

Key Achievements

•Installation of bespoke I&M system on the Thames River retaining wall
•Design and Planning to ensure project criteria was fulfilled.
•Establishment of manual monitoring scheme and handover to main client for further daily surveys.

The project

National Grid Gas is enhancing the gas supply system in London by replacing part of medium pressure gas mains beneath the Thames River. The new pipeline will run through a new tunnel beneath the Thames River comprising:

(1) A 7.5m (ID) shaft to launch a Pipejack TBM at Chelsea, (2) A 6.0m internal diameter (ID) shaft to receive, and facilitate the recovery of the Pipejack TBM at Battersea (3) A 1.8m ID tunnel installed by means of Pipejack between the shafts. The tunnel length is approx. 330m and ranges in depth from -21.1m OD to -24.3m OD.

The challenge

Working on the River Thames retaining wall with limited access due to tides and to waterproof HLC & Tilt meter systems to be capable of withstanding the daily high tides.

The solution

Design, manufacture and installation of bespoke HLC & Tilt meter systems filled with a F4P Gel to isolate electrical components making the system’s degree of protection IP68.

Periodical manual prism surveys are to verify the automatic system performance. Precise levelling around the shafts and park areas control the level of settlement during the process of shaft sinking.