关键词: 冻结黏土, 单轴抗压强度, 蠕变试验, 内变量, 温度效应, 蠕变模型

Abstract: Safety evaluation of artificial freezing method depends on the creep characteristics of frozen soil. Uniaxial compression test and staged loading creep test were conducted at temperatures below 0 ℃ on undisturbed clay collected from a deep mine in Shanxi Province to study the failure mode and mechanism of the frozen soil as well as the form of uniaxial compressive strength and creep curves at different temperatures. The uniaxial compressive strength varied linearly with the declining of temperature, and the creep value under the same loading stress also decreased with the drop of temperature. In line with the internal variable theory, strain was considered as the internal state variable to describe the creep characteristics of frozen soil. The fitting curve of logarithm of creep and creep rate suggested a linear relationship between them. On such basis, an internal variable creep model that was only related to temperature and loading coefficient was established. Parameters of the model could be determined by fitting curves. The fitting of test data into the model showed that the model could better reflect the creep of frozen clay with less model parameters, and is convenient for engineering application.

Key words: frozen clay, uniaxial compressive strength, creep test, internal variable, temperature effect, creep model