Abstract
Field indentation tests to measure ice load have been conducted at Notoro lake in Hokkaido, using an indentation test apparatus. Test data and observations on failure of an ice sheet (first-year ice) have been accumulated. The failure of the ice sheet is discussed based on the observation of the contact surface between indentor and ice sheet. The simplified model for flaking failure is proposed under the assumpution that the failure continues at constant shear strength of the ice. The model roughly matched the flaking failure of the ice sheet in the field test. Cleavage cracking criterion and bending failure were also discussed in relation to fracture toughness and Euler's equation.
