ANALYSIS OF MECHANICAL CHARACTERISTICS OF FROZEN CLAY AND MODIFIED S-M CREEP MODEL¹⁾

To describe the mechanical characteristics of the mine soil layer constructed by the artificial freezing method, the uniaxial compressive strength test and the uniaxial compression creep test are carried out by using the remolded soil samples of a certain mine, and the stress-strain curves and the creep curves of the remolded frozen clay at different temperatures and loading grades are obtained. Experimental results show that the uniaxial strength of the soil is higher at a lower frozen temperature; The creep deformation of the soil increases with the increase of the stress level at the same frozen temperature; The isochronous stress-strain curve of the uniaxial compression creep deviates with respect to the strain axis with time. The soil sample experiences two stages of the initial creep and the stable creep, with a tendency to enter the accelerated creep stage in a higher stress level. By modifying the meaning of the parameters in the Singh-Mitchell model and with consideration of the influence of temperature, the improved S-M creep explicit model of the artificial frozen clay is obtained. Then the parameters of the S-M creep explicit model are optimized by using the particle swarm algorithm. Compared with the modified S-M explicit model, the calculated values are in good agreement with the experimental data, which indicates that the modified S-M creep explicit model can well simulate the creep characteristics of the deep frozen clay. The modified S-M creep explicit model provides a new method for the creep calculation of the artificial frozen soil.