WHERE ARE THE TUNNELS AT BATTERSEA?

As part of the proposed development of Battersea Power Station, the iconic London landmark, it was necessary to carry out a subsurface multi-beam survey to identify the location and structure of inlet and outlet tunnels. The exact location of the tunnels was unknown as accurate survey maps of the historic building were unavailable

USING A SPECIALLY commissioned multibeam sonar system together with a verticality probe, RG partnered with specialist technology companies, Geoterra and Flodim. A subsurface multibeam sonar survey was undertaken, focussing on the coolant water outlet tunnel via pre-drilled boreholes.

The boreholes and tunnel were geo-referenced to OSGB 36 and Newlyn level datum. Site conditions were very challenging as surveying had to be carried out in tunnels which were either ?lled with water containing sediment or thick mud.

The partners provided the contractor with a complete set of geo-referenced 3D point cloud data and updated topographical survey plans of the outlet tunnel, combining each of the sonar surveys. Surveying of the inlet tunnel was not possible as this was completely full of hard, compacted mud. The multibeam sonar data would then be analysed and interpreted, together with an updated topographical survey plan, to plan detailed design of the future building works above.