| abstracts | In this paper the problem of interaction between a coherent floating ice field and a fixed, rigid, vertically-walled circular cylinder is investigated. The ice cover, of horizontal dimensions significantly larger than the characteristic size of the structure, is assumed to be driven against the cylinder by wind drag forces. The ice is treated as a viscous-plastic material, in which the permissible stress states in the horizontal plane are bound by an elliptic yield curve. By using an associated flow rule, a constitutive law, involving two parameters defining the ice strength in compression and much smaller strength in extension, is derived in order to describe the behaviour of the material. The law predicts distinct responses during yield (occurring at high strain-rates) and during the flow when the yield condition does not apply (at lower strain-rates). The results of numerical calculations performed by a finite difference method illustrate, for chosen ice rheological parameters, the distribution of contact stresses at the ice – structure interface. Two forms of boundary conditions at the cylinder wall, free-slip and no-slip, are considered, and their effects on the horizontal loads sustained by the structure are examined. In addition, the results for the viscous-plastic rheology of ice are compared with those obtained on the assumption of a purely viscous behaviour of ice. |