Experimental fracture and mechanical properties of Antarctic ice: preliminary results

An experimental study of the fracture mechanics and rheology of ice from the Ronne Ice Shelf, Antarctica, is currently being undertaken. The apparent critical stress-intensity factor (or apparent fracture toughness, K Q) for crack propagation has been measured using a three-point bend method for inducing crack growth perpendicular to the axis of cylindrical ice-core specimens. Tensile crack nucleation under applied uniaxial compressive stress has also been evaluated. Both methods have allowed a profile of ice elastic and fracture properties with depth through the ice shelf to be constructed. Preliminary results indicate that the measured elastic modulus increases with depth through the firn and upper meteoric ice before reaching a constant value in the deeper, dense meteoric and basal marine ice. The resistance to fracture, as measured by changes in apparent fracture toughness and crack-nucleation stress, increases with depth right through the firn and meteoric ice layers. A simple fracture mechanics model applied to the Ronne Ice Shelf indicates that crevasses form from small surface cracks, less than 40 cm deep, which quickly grow to depths of 40‐60m and then remain stable.

Details

Publication status:
Published
Author(s):
Authors: Rist, M.A., Sammonds, P.R., Murrell, S.A.F., Meredith, P.G., Oerter, H., Doake, C.S.M.

Date:
1 January, 1996
Journal/Source:
Annals of Glaciology / 23
Page(s):
284-292
Digital Object Identifier (DOI):
https://doi.org/10.3198/1996AoG23-284-292