Effects of wetting-drying-freezing-thawing cycles on mechanical behaviors of expansive soil

Cyclic action of wetting-drying-freezing-thawing (WDFT) is an important factor for damages of canals in seasonally frozen regions, which should be taken into account for relevant studies. This paper presents details of an investigation dealing with the effects of wetting-drying-freezing-thawing cycles on the mechanical behaviors of expansive soil by triaxial tests. The results show that the WDFT cycles had a significant impact on the attenuation of expansive soil mechanical properties, which resulted in the decreases of elastic modulus, failure strength, cohesion and angel of internal friction by 12.6% -37.7%, 17.2% -30.9%, 27.6% -43.2% and 4.3% -10.0%, respectively. In the meantime, it is found that the damage variables of specimens in the triaxial tests increased with rising WDFT cycles, and tended to be stable after 3rd cycle. The expansive soil with a higher stress level and a relatively larger drying range in the drying process during the cyclic action of WDFT were damaged more seriously. Additionally, the normalized stress-strain relationship considering the WDFT cycles and confining pressures was proposed. The established relationship can well predict the stress-strain behaviors of expansive soil compared with the experimental results.

Automated summary

This study investigated the effects of wetting-drying-freezing-thawing cycles on the mechanical properties of expansive soil through triaxial tests. The results showed that WDFT cycles significantly impacted the mechanical properties of expansive soil, leading to decreases in various parameters. Damage variables of specimens increased with rising WDFT cycles, but tended to stabilize after the 3rd cycle.