Creep behaviors of artificial freezing columnar ice prepared in successive high-pressure state

In cold regions and artificial ground freezing engineering applications, ice is commonly formed within confined environments. Insufficient understanding of the creep deformation characteristics of such ice may lead to miscalculation of long-term deformation. Nevertheless, significant research gaps persist concerning the effects of freezing pressure on ice creep mechanisms. This study systematically investigates the influence of creep stress, temperature, confining pressure, and freezing pressure on the creep behaviors of confined pressure-frozen ice. It is revealed that the creep deformation of pressure-frozen ice primarily follows a dislocation creep mechanism, with a slightly elevated stress exponent (n = 3.41 ± 0.31) and creep activation energy (Q = 108 ± 18 kJ/mol). The minimum creep rate initially decreases and then increases as confining pressure and freezing pressure rise. Confining pressure exerts its influence through competition between the pressure melting mechanism and dislocation motion restriction, and freezing pressure dictates the initial dislocation density in pressure-frozen ice. With the freezing pressure being increased from 0.1 MPa to 10 MPa and then to 30 MPa, a 61.87 % reduction and a 15.79 % increase in the minimum creep rate are observed. Based on experimental findings and the Andrade creep model, a creep model accounting for freezing pressure and confining pressure factors is established along the columnar crystal direction. The study aims to provide valuable insights for predicting ice creep deformation in both polar glaciers and artificial ground freezing projects.