Summary: Physical Modelling in Geotechnics 6th ICPMG '06 Ng, Zhang & Wang (eds)
© 2006 Taylor & Francis Group, London, ISBN 0-415-41586-1
Centrifuge modelling of scouring ice keels in clay
I.S.S. Schoonbeek & H.G.B. Allersma
Delft University of Technology, Delft, The Netherlands
ABSTRACT: Oil and gas produced in the Arctic seas is transported by offshore buried pipes. In some areas,
however, the estimation of a safe burial depth is hampered by the possibility that ice masses can make trenches
in the sea floor and damage the pipe, this process is known as "ice scouring". In order to make a safe design,
knowledge is required of the soil deformation under an ice keel scouring the soil. Since it is difficult to examine
ice scouring in a field test, tests have been carried out in the geotechnical centrifuge of the University of Delft.
Several parameters were varied, such as speed, undrained shear strength, scour depth and multiple scouring.
A grid was placed on the clay sample so that the complex deformation pattern could be visualized clearly.The soil
deformation was measured by means of image processing and the horizontal and vertical loads were measured.
The tests have shown interesting relationships between these parameters and the subgouge deformation. Under
some circumstances, shear bands and deep cracks could be observed. The test results indicate that the depth of
subgouge deformation can be estimated by the undrained shear strength of the soil.
Scouring ice keels is a class of soil-structure interac-
tion problem associated with large soil deformations,
shearbands and cracks. These problems do not lend