Rheology of columnar-grained ice

Creep of columnar-grained ice, under uniaxial compressive force normal to the columns, is shown to be composed of an instantaneous elastic response followed by a delayed elastic and viscous deformation. Both the delayed elastic and viscous strains are shown to have equal activation energies. Thus, this ice can be considered as a thermorheologically simple material with a nonlinear stress dependence. A simple phenomenological relationship has been developed that can be used for further analysis of the creep compliance function presented in a normalized form.