Effects of freeze-thaw on settlement of fine grained soil subjected to cyclic loading

Abstract

The dominant soil deposits in the seismically active Arctic region are of fine-grained characteristics. Behavior of such soil deposits under dynamic loading is typically influenced by the freeze-thaw phenomenon as well as the variation of the ground temperature. In this extensive experimental study, settlement of fine-grained soils due to seismic loading is investigated. Reconstituted soil samples were tested under laboratory conditions to study the effect of freeze-thaw and lowered ground temperature. A strong correlation between the settlement potential and developed excess pore pressure during cyclic loading was found to exist for all freeze-thaw conditions. The settlement increased with increasing excess pore pressure. Subjecting the soil to freeze-thaw cycles decreased the settlement potential. A substantial decrease in volumetric strain of the soil occurred within the first two cycles of freeze-thaw. The number of dynamic loading cycles and the level of induced shear strain were also found to influence the settlement; the larger the number of loading cycles and induced shear strain the greater the settlement, for all freeze-thaw conditions. Another factor affecting the cyclic settlement was the variation in ground temperature. The soil experienced the smallest settlement at near-freezing temperature of 0.5 °C.