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| Deformation characteristics of frozen clay with considering the influence of mean principal stress |
| LEI Lele1，WANG Dayan2，LI Dongwei1，WANG Yongtao3，ZHANG Binlong2 |
| (1 School of Civil and Architecture Engineering，East China University of Technology，Nanchang，Jiangxi 330013，China；2 State Key Laboratory of Frozen Soils Engineering，Northwest Institute of Eco-Environment and Resources，CAS，Lanzhou，Gansu 730000，China；3. Institute of Transportation，Inner Mongolia University，Hohhot，Inner Mongolia 010070，China) |
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Abstract In order to study the effect of stress level on the deformation characteristics of frozen clay during loading process，a series unidirectional rotation of the principal stress axis tests was conducted on frozen clay under different mean principal stress at －10 ℃ using a frozen soil hollow cylindrical apparatus in this study. The experimental results indicate that，the mean principal stress p has a great influence on the axial strain and shear strain in unidirectional rotation loading process. The ratio of difference between maximum and minimum axial strain to minimum axial strain can reach 121.7%，and axial tensile strain decreases with the increase of p-value. The peak value of shear strain lags behind the peak value of shear stress，showing strong viscoplastic deformation characteristics. And the larger the shear strain is during loading process，the greater the degree of lag behind of
shear strain is. At lower p-value，the strength of frozen clay increases with the increase of p-value. However，when the p-value exceeds the threshold value，it will decrease with the increase of p-value. The threshold p-value is reduced with the increase of intermedia principal stress. After the unidirectional rotation tests，there is obvious plastic shear strain in specimen. By analyzing the curve of p-value versus plastic shear strain，four stages can be got，which is strengthening，weakening，weak strengthening and weakening again.
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2021, Vol. 40 
