Prediction of failure in atmospheric ice under triaxial compressive stress

- Atmospheric ice has been prepared under specific conditions inside the icing wind tunnel.
- Triaxial tests have been performed on cylindrical specimens under various experimental conditions.
- Confined compressive strength of atmospheric ice depends highly on temperature, strain rate, and confinement.
- Mohr-Coulomb and Hoek-Brownfailure criteria have been examined to model the failure of atmospheric ice.

Triaxial experiments have been carried out on atmospheric ice samples under various conditions. Samples have been obtained from ice accumulated on a rotating cylinder inside the INGIVRE (Canada Research Chair on Atmospheric Icing Engineering of Power Networks) icing wind tunnel. Samples were tested at the same temperature at which they had been accumulated: at − 5, − 10 and − 15 °C under three strain rates 10− 4, 10− 3 and 10− 2 s− 1. Tests were conducted under various confinement pressures. At a temperature close to the melting point, atmospheric ice strength increases up to a certain value of confinement, and then decreases significantly. In the case where atmospheric ice strength increases continuously with increasing confinement for lower temperatures, the Mohr-Coulomb and Hoek-Brown failure criteria have been investigated in order to predict the failure of atmospheric ice.