Author(s): T. Takeuchi; S. Kioka
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Keywords: Ice load; Deformed ice; Consolidated layer; Hydraulic structures
Abstract: Offshore structures in ice-covered sea areas are subject to loads due to sea ice movement. Among several types of sea ice, it is important to estimate ice load imposed by deformed ice such as rubble ice and ridge ice, since the thickness of deformed ice is much larger than that of the surrounding level ice. Further, the consolidated layer of deformed ice is more important in ice load estimation than the sail and keel parts due to its higher strength. Takeuchi et al. (2004,2006) reported that ice loads in the ductile range impose larger loads than in the brittle range. This was verified by indoor tests using a consolidated layer model of deformed ice. However, there is little information available on the creep properties of consolidated layers of deformed ice, even though it has been reported that the thickness of the consolidated part is two to three times that of the surrounding level ice sheet (Timco and Goodrich; 1988). In the study, creep tests were conducted using ice blocks to model the consolidated layer of deformed sea ice under constant loading in a cold room to observe the deformation in comparison with that of level sheet ice. The effects of normal stress and ice block size composing the consolidated layer were investigated under constant ice temperature. The applicability of Norton’s (Glen’s) law of secondary creep was also investigated.
Year: 2010