Triaxial compression strength for artificial frozen clay with thermal gradient

ZHAO Xiao-dong(赵晓东), ZHOU Guo-qing(周国庆), CHEN Guo-zhou(陈国舟)

(State Key Laboratory for Geomechanics and Deep Underground Engineering
(China University of Mining and Technology), Xuzhou 221008, China)

Abstract:A series of triaxial compression tests for frozen clay were performed by K₀DCGF (freezing with non-uniform temperature under loading after K₀ consolidation) method and GFC (freezing with non-uniform temperature without experiencing K₀ consolidation) method at various confining pressures and thermal gradients. The experimental results indicate that the triaxial compression strength for frozen clay in K₀DCGF test increases with the increase of confining pressure, but it decreases as the confining pressure increases further in GFC test. In other words, the compression strength for frozen clay with identical confining pressure decreases with the increase in thermal gradient both in K₀DCGF test and GFC test. The strength of frozen clay in K₀DCGF test is dependent of pore ice strength, soil particle strength and interaction between soil skeleton and pore ice. The decrease of water content and distance between soil particles leads to the decrease of pore size and the increase of contact area between particles in K₀DCGF test, which further results in a higher compression strength than that in GFC test. The compression strength for frozen clay with thermal gradient can be descried by strength for frozen clay with a uniform temperature identical to the temperature at the height of specimen where the maximum tensile stress appears.

Key words:artificial frozen clay; triaxial compression test; thermal gradient; strength