This paper shows the different in the volumetric strains between the Oedometer tests with different soaking durations and the unsaturated triaxial tests. The disturbed samples were taken from Al-Najaf city in Iraq. All specimens have the same high gypsum content of 29%. For Oedometer tests, the specimens are tested in the different soaking durations; the first is in natural moisture content then half hour, one week and two weeks. While in triaxial tests, a wetting induce has been conductive to estimate the volumetric strains under two stress levels (2.5 and 5 kg/cm2) with presence of matric suction in four levels; initial matric suction (ψo), 0.6 ψo, 0.3 ψo and zero ψ. The results from unsaturated triaxial tests indicate that the volumetric strains are increased as matric suction decreased and the trend of stress-strain curve became steep. While from Oedometer tests, when the specimen is soaked in natural and for a half hour, the volumetric strains are not significantly changed and close to the high matric suction. When the soaking time is increased to a one week, there is relatively increase in volumetric strains. But after two weeks soaking in Oedometer cell, the volumetric strains are very clear in increasing and close to the volumetric strains from unsaturated tests in low matric suction

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