Microstructure damage behavior and change characteristic in the creep process of frozen soil

Based on the data of uniaxial creep tests artifically frozen loess and polyerystal ice at the temperatures of -5°C and -10°C and the results of structure duplication-electronscope, this paper discussed the microstructure damage behaviour and change characteristics of frozen soil in the creep processes: non-stable, viscoplastic flow, progressive flow and failure stage. The test results showed that the creep stress level is a determinative factor of controlling damage behaviour. And the structure damage, oriented degree of mineral grain and extension of microcrack controlled the hardening and softening behaviour in the creep process. The study has advanced the evidences for creating the damage theory of frozen soil.