Abstract: A transient water release and imbibitions(TWRI) method together with Van Genuchten(1980) soil-water characteristic curve models and Mualem(1976) hydraulic conductivity function model was used for the inversion calculation of soil water-force parameters and the soil water characteristic curve(SWCC). The Malan loess at Zichang County in Shaanxi Province was selected as research object. Test results showed that the SWCC of soil samples under different drying and wetting states had apparent hysteresis effect. The air-entry value and saturated volumetric water content under drying state was 26 kPa and 48% respectively. Parameters related to pore size distribution changed slightly under different drying and wetting states. In order to verify the TWRI test results, steady-state test was carried out on the same soil sample using the volume 2 Bar pressure plate apparatus to study the relationship between their matrix suction and volumetric water content. By comparing the test results, it’s found that the test results of TWRI agrees well with that of pressure plate apparatus under low suction (0-300kPa). It has short test time and wide test range of matric suction.

Key words: unsaturated Malan loess, soil-water characteristic curve, transient water release and imbibitions(TWRI) method, volume pressure plate