EXPERIMENTAL RESEARCH ON FAILURE CRITERIA OF FRESHWATER ICE UNDER TRIAXIAL COMPRESSIVE STRESS

In order to know the mechanical properties of frozen wall which contain ice, solve the ice-rock coupling problems, provide believable parameters for ice engineering design and numerical simulation analysis, it is necessary to research the ice mechanics under triaxial compressive stress. Taking the frozen shaft construction of Shilawusu coal mine in Inner Mongolia Autonomous region Dongsheng coal field as the project background of the research. The similarity columnar ice specimens are fabricated in the laboratory based on the field data. A series of tests were performed on artificial freshwater columnar ice under triaxial compression at 4 group temperatures and 7 group confining pressures by using the TDW-200 frozen soil triaxial test system. The loading rate of the series of tests is 0.5 mm/min, and the loading direction is perpendicular to the crystal axis of ice. The results show that, when the experimental temperature is constant, the plasticity of columnar ice increases with increasing confining pressures. When the experimental confining pressure is constant, the brittleness of columnar ice increases with decreasing temperature. Within the range of test temperature, the strength of columnar ice and polycrystalline ice increase with the increase of confining pressure and temperature. The strength of columnar ice is higher than polycrystalline ice at the same conditions. The non-linear relationship between deviatoric stress and confining pressures is explained by D-A model or Teardrop model. From the point of view of integrated advisement, the D-A failure criteria is more reasonable to describe the failure characteristics of the freshwater ice. The conclusions can provide some scientific references for ice-rock coupling research and numerical simulation under the same conditions.