Author(s): Ase Ervik; Aleksey Shestov
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Keywords: No Keywords
Abstract: Ice ridge properties such as geometry, macro-porosity and strength influence first-year sea ice ridge loads. These properties change during the life of a first-year sea ice ridge. The topic of the present paper is the evolution in strength and macro-porosity, especially rubble macro-porosity, during the melt season. Four drifting first-year ice ridges were investigated in the Arctic Ocean from May 21 st to June 23 rd 2015. The macro-porosities were obtained by mechanical drilling averaged over several boreholes along a drill transect. For two of the ridges, the drilling was repeated along the same transect, with approximately a week between measurements. From the repeated measurements, the rubble macro-porosity decreased as the melting progressed. The most severe decrease occurred in the smallest and youngest ridge. Furthermore, a gradation curve for the ice block length over the thickness ratio was obtained for one ridge sail. This measurement was used to qualitatively evaluate the initial rubble macro-porosity before consolidation. Additionally, the drilling hardness was measured. The decrease in hardness followed the increase in temperature. Vertical ice cores tested in-situ under uniaxial compression agreed with the registered drilling hardness.
Year: 2016