Flatjack Methods of In-Situ Measurement of the Mechanical Properties of Sea Ice

The objective of this report is to describe techniques for conducting measurements of several of the mechanical properties of sea ice by in-situ methods. The tests described all involve the use of flatjacks of various shapes for supplying a known stress field into the ice. The geometry of the sample being tested is defined by introducing internal boundaries into the ice sheet by cutting slots or installing layers of plastic film. The resulting deformation of the ice is measured by strain gages embedded in the test sample or by linear variable differential transformer transducers (LVDT’s) or linear potentiometers mounted on pegs which, in turn, are frozen to some depth in the sample. Test procedures for conducting uniaxial and biaxial compression tests, indirect tension tests and a simulated direct shear test are described. These yield information on Young’s modulus, Poisson’s ratio, creep properties, and strength under various loading conditions.