The creep behaviour and strength of ice under the multiaxial loading conditions are discussed in the paper basing on the results of laboratory experiments with an artificial saline ice. Possible modifications of mathematical models early proposed by the authors are investigated in order to take into account the regularities of multiaxial tests.
Ice-to-structure interaction is one of the key problems which should be carefully investigated for offshore structures successful designing and operating in Arctic regions and also in all regions where sea ice cover, floes, icebergs or ground ice can exist. It is well-known for most realistic situations in engineering practice that the complex, multiaxial stress-strain state arises in ice under the interaction, affecting strongly the contact loads and displacements e.g., when an ice floe strike the leg of structure or when a structure foundation bases on the ice layer. Nevertheless, most of experimental data concern the simplest loading geometry (uniaxial compression-tension, shear and bending tests). Up to now, only few work is known presenting original test results of multiaxial ice behaviour, mainly of fresh-water ice: Rigsby (1958); Haefeli et ale (1968); Hausler (1981); Jones (1982,1983); Richter-Menge et ale (1986); Timco and Frederking (1983). In this paper, strength and creep proper~ ties of an artificial saline ice are investigated by the device of stabilometric type providing the uniform stress state б1 > б2 = б3 through the samples (б denote the principal stress vector components). The main goal is to estimate the effect of hydrostatic pressure on both quasi-instantaneous and long-term strength, as well as on the shear and volume creep strains development and also to find a suitable mathematical description for such influence.
All tests were carried out with quite identical cylindrical samples (diameter, d=4l,5mm; height, h=100mm) of saline ice.