Author(s): Michael Demuth; Terry Prowse
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Keywords: No Keywords
Abstract: This paper describes methods to: i) interpret effective strain modulus from full borehole jack indentor tests; and ii) obtain strain modulus profiles in relatively thin icecovers using shallow indentation. Specifically, a cavity expansion model for the borehole jack indentor is evaluated for its ability to determine the strain modulus of deteriorating freshwater ice. In general, the model does not replicate the pressure-displacement curve from jack tests of 0°C columnar ice, thereby negating a parametric determination of strain modulus. A less rigorous but useful approach is proposed by defining indentor-ice deformation moduli directly from the pressure-displacement characteristics of the jack test. Examples of these moduli are presented using previously obtained jack test data for deteriorating columnar ice. Data indicate that relationships between such moduli and the actual strain modulus of ice can be established provided that their relationship to porosity and other physical characteristics is known. The importance of evaluating profile variability for floating ice covers undergoing flexural deformation is described, and to that end, the utility of the borehole jack test is established.
Year: 1992