The 20 September meeting of the British Geotechnical Association will look at the challenges facing a project team charged with stabilising the wreck on contaminated Second World War submarine off the coast of Norway.
Norwegian Geotechnical Institute technical advisor Per Magnus Sparrevik will present the historical background, environmental and geotechnical conditions faced by the Norwegian Coastal Administration undertaking challenging remediation work to protect the marine environment from the toxic legacy of U-864, a German submarine sunk by the British Navy outside the west coast of Norway near the end of the Second World War.
As the sloping seabed at the wreck site was unstable, the first step was to install a large counter fill to prevent sliding of the heavily contaminated sediments. The large counter fill was successfully installed in June 2016 at the foot of the unstable slope where the wreck is resting. A rigorous monitoring program of both environmental and geotechnical parameters indicated that no further spreading of contaminated sediments occurred during the construction of the counter fill.
Initial piezometer readings show that the build-up of excess pore pressures beneath the counter fill during construction matched the predictions very well. The ongoing autonomous recordings of pore pressure and settlement data are vital to verify the rate of consolidation and determine when the slope is sufficiently stable to allow for further counter filling and final capping of the wreck and contaminated sediments.
The meeting will be held on 20 September between 6pm and 8pm at the Institution of Civil Engineers.
Register for the event online at: https://www.ice.org.uk/events/mercury-filled-u-boat-wreck-stabilisation-london