A temperature model has been developed that describes the ice strength in a multiaxial stress state over a wide spectrum of negative temperatures. The model takes into account the anomalous behavior of ice under high hydrostatic pressure, when its strength reaches a maximum, and then gradually decreases with the pressure increase. It has been shown that strength of ice under high hydrostatic pressure is described by an extended Drucker-Prager (parabolic) strength criterion with only three fundamental parameters, ice cohesion, internal friction angle, and ice melting pressure, which all have a definite physical meaning and are functions of temperature. The model has been verified using test data on the strength of iceberg ice and laboratory made polycrystalline freshwater ice under triaxial compression at strain rates between 10−3 and 10−5 s−1 over the temperature range between −1°C and −40°C.
Studies of ice strength in the second part of this century attracted efforts of a number of researchers. Their attention was focused on investigation of ice strength as a function of the strain rate, temperature, grain size and other factors mainly in simple stress-strain, uniaxial compression. During the last two decades, however, the attention of researchers was shifted to investigation of the mechanical behavior of ice, particularly the strength of ice, in a complex stress-strain state such as triaxial compression. In a general case, strength of ice in a multiaxial stress state, when other conditions (the type of ice, its structure, the grain size, etc.) are equal, can be presented as (equation 1 shown in paper). The first studies of the effect of low confuting pressure on creep strength of ice under triaxial (02 = 03) compression were carded out by Sayles (1974).
