2017 Volume 73 Issue 2 Pages 131-140
Prediction of the permeability of freeze-thawed soils is significantly important in the case that a final disposal site is being constructed in a cold region or a large-scale frozen earth wall is operating for a long period. Although a large number of knowledge has been obtained, it still is difficult to predict the permeability of freeze-thawed soils in a practical level. This study proposes a permeability prediction method of freeze-thawed soils based on the experimental findings.
In this study, freeze-thaw experiments were conducted with saturated fine-grained soils with different pre-consolidation pressures and overburden loads in order to predict the permeability of freeze-thawed soil. Two types of freeze-thawed experiments were carried out with the artificial ground freezing on-site construction condition considered, one is one-dimensional freeze-thaw test, and the other is horizontal displacement restrained freeze-thaw and vertical permeability test, which enables horizontal freezing under restricted horizontal displacement.
The result has revealed that the permeability of freeze-thawed soil is obviously influenced by overburden test pressure rather than pre-consolidation pressure, over-consolidation ratio and frost heave ratio. The result suggests that the permeability of freeze-thawed soil can be predicted by the freeze-thaw test for which the effective overburden pressure is considered, rather than strength or hardness of the ground materials and other freezing conditions are. Moreover, void ratio and permeability after freeze-thaw tended to approach the value of unfrozen soils with an increases of pressure. Furthermore, it has been suggested that the permeability of freeze-thawed soils in an actual artificial ground freezing method might be increased by non uniformity in distribution of void ratio due to frost heave.