CREEP OF SNOW AND ICE.
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H
Pagination or Media Count:
Constant load creep tests in uniaxial unconfined compression were performed on samples of sintered snow and bubbly polycrystalline ice. Nominal axial stresses were in the range 0.1 to 1.0 kgfsq cm for snow, and 0.5 to 20 kgfsq cm for ice. The range of temperatures investigated was from -0.5 to -34.5C. Assuming creep to follow the Arrhenius relation, values of apparent activation energy for secondary creep under a nominal axial stress of 0.5 kgfsq cm varied from 10.7 kcalmole for ice of density 0.83 gcu cm to 17.8 kcalmole for snow of density 0.44 gcu cm. The dependence of strain rate epsilon on stress sigma for polycrystalline ice subjected to stresses in the range 0.5 to 20 kgfsq cm at temperatures of -4 and -10C could best be described by a relation of the form epsilon C sub 1 sigma C sub 2 sigma to the 3.5 power where C sub 1 and C sub 2 are constants for a given ice type. It is suggested that the creep of polycrystalline ice depends on at least two distinct mechanisms in the stress range studied. If each mechanism has its own characteristic activation energy, the apparent activation energy measured in creep experiments may well vary with stress level. In snow subjected to a given nominal stress, such an effect should be reflected in variation of apparent activation energy with bulk density. Author
- Snow, Ice and Permafrost