ACROSS-COLUMN CRACKS AND AXIAL SPLITS IN S2 SALINE ICE UNDER COMPRESSION

Experiments on plate-like specimens have established that across-colum n cracks form within S2 (columnar) salt-water ice when compressed unia xially along a direction inclined to the long axis of the grains. Wing cracks initiate from the across-column cracks and lengthen into axial splits when the ice is rapidly deformed; correspondingly, the macrosc opic behavior changes from ductile to brittle. The across-column crack ing is attributed to grain-boundary sliding, and the splitting to the suppression of crack-tip creep.