Author(s): M. Inoue; Y. Yamauchi; T. Ebinuma
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Keywords: No Keywords
Abstract: Antarctic sea ice samples were taken from first-year land-fast ice sheet at Ongul Strait and at Breid Bay during the Antarctic summer of 1985 to 1986, when the Japanese Antarctic observation ship’Shirase' transported the 27th mission of the Japanese Antarctic Research Expedition. These samples were then shipped to Tsu in Japan. Physical features of the Antarctic sea ice were examined, and uniaxial compression tests and shear tests were performed under -10 °C in a newly built cold room of NKK Corporation. Three types of sea ice were recognized: granular ice, columnar ice with preferred c-axis orientation in the northeast direction, and short columnar ice with weak-oriented c-axis in the horizontal plane. Strain rate sensitivity of horizontal compressive strength for these types of ice was found to be almost identical. The granular ice was, however, slightly stronger than other types of ice which had an identical strength value, under similar strain rate and total porosity. In examining the compressive strength as a function of total porosity, individual linear relationships between the strength and the square root of total porosity were obtained for granular ice and for columnar ice. The lateral strain was also measured as a function of strain rate. The resulting strain ratio at failure ranged from 0.4 to 0.7. As for shear tests, the vertical shear strength correlated well with the total porosity of sea ice. The difference in shear strength was not observed among the ice types.
Year: 1988