Elastic Properties of the Remolded Soil during Freezing and Thawing Cycle by Bender Elements

Abstract

The elastic properties such as shear moduli and shear moduli of freezing and thawing soil are important parameters for analyzing the stress distribution and thaw-subsidence of freezing soil and deformation of well casing embedded in freezing soil. This paper presents elastic properties obtained by conducting laboratory testing of sand samples from the area of soil. The bending elements were used to measure the shear wave (S-wave) velocities for evaluating the shear moduli during freezing and thawing. Nine pairs of testing specimens were conditioned from 25°C to -25 °C at an interval of 5 °C for examining the temperature effects during freezing and thawing process, respectively. The test parameters included dry density (1.6,1.8,2.0 g/cm3) and moisture content(6%,9%,the saturation). Test results showed that the wave velocities and the shear moduli in all types of specimens tested exhibit sharp change when the temperature adjacent to 0 °C, likely due to non-uniform freezing point depression caused by the varying structure among specimens. The increase of dry density has positive effect on shear modulus. However, the moisture content has a dual effect on the strength of the sand soil.