Ice-sheet flow conditions deduced from mechanical tests of ice core
Ice-sheet flow conditions deduced from mechanical tests of ice core
复制标题
从冰芯力学测试推导出冰盖流动条件
DOI：
10.3189/172756499781820950
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发表时间：
1999
影响因子：
2.9
通讯作者：
P. Duval
中科院分区：
文献类型：
--
作者：
A. Miyamoto;H. Narita;T. Hondoh;H. Shoji;K. Kawada;O. Watanabe;D. Dahl;N. Gundestrup;H. Clausen;P. Duval
对格陵兰冰戈尔项目（GRIP）深冰芯样品进行了现场和冷室实验室单轴压缩试验，以了解大冰盖的冰流行为。实验在恒定应变速率（A型）和恒定载荷（B型）条件下进行。从1327-2922米的54个单轴压缩试样被选中。制备每个试样（25 mm x 25 mm x 90 mm），其单轴应力轴与芯轴倾斜45°，以检查底面平行于水平面的坚固单最大冰芯样品的流动行为。冰盖。冰流增强因子随深度的增加而逐渐增加，直到大约2000 m。这些结果可以解释为四阶施密德因子的增加。在2000 m深度以下，流动增强因子增加到20-30左右，具有相对较高的变异性。当Schmid因子> 0.46时，获得的流动增强因子高于由实验得到的流动增强因子。测量轴浓度。从具有混浊带状结构的试样中获得了较高的流动增强因子值。据透露，云带影响冰的变形过程，但细节仍不清楚。
Abstract Uniaxial compression tests were performed on samples of the Greenland Ice Gore Project (GRIP) deep ice core, both in the field and later in a cold-room laboratory, in order to understand the ice-flow behavior of large ice sheets. Experiments were conducted under conditions of constant strain rate (type A) and constant load (type B). Fifty-four uniaxial-compression test specimens from 1327-2922 m were selected. Each test specimen (25 mm x 25 mm x 90 mm) was prepared with its uniaxial stress axis inclined 45° from the core axis in order to examine the flow behavior of strong single-maximum ice-core samples with basal planes parallel to the horizontal plane of the ice sheet. The ice-flow enhancement factors show a gradual increase with depth down to approximately 2000 m. These results can be interpreted in terms of an increase in the fourth-order Schmid factor. Below 2000 m depth, the flow-enhancement factor increases to about 20-30 with a relatively high variability When the Schmid factor was > 0.46, the enhancement factor obtained was higher than expected from the .-axis concentrations measured. The higher values of flow-enhancement factor were obtained from specimens with a cloudy band structure. It was revealed that cloudy bands affect ice-deformation processes, but the details remain unclear.