Water retention behaviours of intact loess exposed to freeze-thaw cycles
Freeze-thaw acting is an important factor that can't be ignored in engineering disasters such as lo-ess slope slump and roadbed subsidence.Water retention behaviour is the key physical property for analyzing the hydraulic-mechanical properties of unsaturated loess,and it needs to be further studied that how freeze-thaw cycle affects water retention behaviours of loess.This test took intact loess after freeze-thaw cycles as re-search objects and studied how both the number of freeze-thaw cycles and the water content before freeze-thaw affect the soil-water retention curve(SWRC)and its characteristic parameters.The results show that the effect of freeze-thaw cycles on SWRC is fluctuating,and the degree of influence is controlled by the number of cycles and the initial water content before freeze-thaw.The relationship between saturation and ratio of suction(ratio between suction and air-entry value)can be normalized under different freeze-thaw conditions.By establishing quantitative relationship between the air-entry value and the structure index,a modified water-retention model was proposed to consider the effect of freeze-thaw cycles uniformly.The effect of freeze-thaw cycle conditions on the SWRC of intact loess is preliminarily confirmed,which can be reflected by the change of air-entry value caused by the change of soil structure index.
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