Author(s): J. S. Melton; E. M. Schulson
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Abstract: The deformation microstructure of S2 columnar saline ice under triaxial compressive loading was investigated at -I0C at strain rate =4 x 10-5 s-1 The confinement ratios (R21=022/011 and R31=On/ (11) varied between 0 and 1, sigma11 and sigma22 are the normal stresses applied in two orthogonal directions across the columns and 033 is the normal stress applied along the columns. The ice remained macroscopically ductile for all loading paths. though the microstructure at a given strain changed with confinement. At R21:50.50 inelastic deformation was mostly plane strain within the XI-X2 plane, occurring most likely by basal slip. Subgrain growth and across-column cracks (200-400 cracks/m2) were observed after 3% deformation. At R21>0.5 the deformation was more three-dimensional, with the crack density increasing by an order of magnitude as R21 approached unity. Sub grains as well as dynamic recrystallization were observed after 3% deformation. The observed deformation microstructure did not account for changes in the flow behavior of the ice.
Year: 1998