STUDIES ON ICE SHEET DINAMICS BY AN ANISOTROPIC FLOW LAW

本研究的目的是对Azuma(1994)提出的冰的各向异性流动规律进行实验验证，并将其应用到冰盖模拟中。本工作取得的成果如下：1.研究成果。研究了单轴压缩下多晶冰的应变速率分量与冰组分之间的关系。在单轴压缩蠕变试验条件下，测量了三个主要应变率分量，并结合试件的c轴取向组构进行了详细的分析。结果表明，实验测得的应变率分量与Azuma模型计算值吻合较好。.2.多晶冰在双轴压缩下的应力和应变率分量与冰组分之间的关系，约束壁上的正应力与压应力的比值随变形而变化。各向异性流动定律可以定量地解释这些实验结果。利用Azuma模型建立了冰盖结构演化的模型。

The objective of this study is to verify experimentally the anisotropic flow law of ice proposed by Azuma (1994) and incorporate it to ice sheet modeling. The results obtained by present work are as follows.1. The relationship between the ice fabric and the strain rate components of polycrystalline ice under uniaxial compression.The measurements of three principal strain rate components were conducted under condition of uniaxial compression creep test and examined in detail with taking into account the c-axis orientation fabric of specimen. It is found that the measured strain rate components agrees well with the calculated values by Azuma's model. .2. The relationship among the ice fabric, stress and strain rate components of polycrystalline ice under biaxial compression.The ratio of the normal stress on restrained wall to the compression stress changes with deformation. The anisotropic flow law can explain quantitatively these experimental results.3. Modeling of texture evolution of ice sheets was developed using Azuma's model.