Relaxation properties of the ice cover

Abstract

The aim of this work was to generalize the known data and conduct experiments to determine the relaxation properties of ice in the ice cover under short-term (no more than 1 min.) loading. The problem lies in the fact that when one is solving applied problems of ice engineering, ice is often considered as an elastic isotropic material, and its stress-strain state (SSS) is studied in terms of the theory of bending of elastic plates. This does not allow performing theoretical calculations when resonant flexural gravity waves (IGW) are excited by moving loads, because under these conditions, the deflections of the ice increase to infinity and the known solutions become unusable. In fact, ice clearly manifests the properties of a quasi-isotropic medium, and the relationship between stresses and deformations is of a viscoelastic nature. It is noted in the work that, depending on the mode in which external loads act on the ice cover, its inelastic properties affect the nature of its behavior in different ways, while the viscoelastic properties of the ice cover are well described by the linear models of Maxwell or Kelvin-Voigt inelastic continuous media. The experimental material is duly processed and analysis is carried out of the results of experimental studies performed in the field by loading the ice cover with balanced loads using a specially made loading device, which was a frame with three supports. The design of the device made it possible to load the ice cover with balanced loads, which made it possible to exclude the influence of false elasticity of water on the results of experiments. For the rheological models of ice behavior indicated, the most probable ranges of changes in the relaxation times of stresses and deformations of the ice cover in the ice conditions considered are given. The results obtained can be used in theoretical studies of ice engineering problems.