Abstract：According to mechanical behavior tests using frozen soil samples from three huge thickness clay strata situated between 400 and 700 m deep in Wanfu mine，the following results are obtained：(1) the stress-strain curves of frozen clay mostly show strain hardening and large yield deformation before the peak stress；(2) contrasting mechanical behaviors of frozen clay under frozen temperatures of －15 ℃，－20 ℃ and －25 ℃，the impact of temperature on creep properties of the deep frozen clay is greater than strength，and －20 ℃ is the limit value for freeze state of the deep-seated clay which can effectively control the creep characteristics of deep frozen wall. The relationship between the deep frozen clay mechanical behaviors and frozen temperature reflected in the results of the test is analyzed to be chiefly relative to the water content and structure of deep frozen clay. The soil samples used in the test are under half-solid state in which the bound water is principal part of pore water. Because the frozn temperature of bound water is much lower than that of gravitational water，when the temperature is lower than －20 ℃，the cementation ice content in the frozen soil increases obviously because of the freeze of bound water，and the impact degrees of cementation ice and inter-particle frictional force on strength of frozen soil become stable，and that leads to the rheological property of frozen soil to decrease sharply.
