Creep of Granular Ice With and Without Dispersed Particles

The effects of silt-sized particles (average diameter of 50 m m) on the compressive creep of polycrystalline ice have been studied at stress levels from 0.1 to 1.45MPa and temperatures of –12 8 C and –10 8 C. Dislocation densities during creep have been estimated using a dislocation-based model of anelasticity. The results indicate that at low concentrations (up to 4wt.% % ), particles increase the minimum creep rate. Power-law behavior with an exponent of 3 was observed for both particle-free ice and ice with 1 wt.% % particles when the stress was \u3e0.3 MPa. In contrast, linear behavior was observed when the stress was \u3c0.3 MPa. Calculations show that the linear behavior is associated with a constant dislocation density, and the power-law behavior is associated with increasing dislocation densities with increasing stress