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Abstract A series of tests considering influences of soil water content，dry density，and anisotropic property，were carried out to research the gas permeability coefficient of unsaturated undisturbed and remoulded Q3 loess，by using a modified triaxial gas permeable apparatus. The results show that，in a lower pressure condition，the results of gas permeability coefficient calculated by Darcy law and Fick law get close to each other；and in a higher pressure condition，the method obtained from Darcy law has an advantage over that got by Fick law. Gas flow of unsaturated undisturbed loess can be expressed by Darcy law. Gas permeability coefficient of unsaturated undisturbed loess decreases with the increase of water content and dry density；and this variation is more obvious in excess of optimum water content. Gas permeability coefficient of vertical undisturbed loess samples is greater than that of horizontal samples in the same buried depth because of anisotropic property. Comparing with gas permeability coefficient of undisturbed loess samples in case of same dry density，the influence of water content on that of remoulded loess is more significant. According to test data，formulas are proposed to compute gas permeability coefficient considering the influence of dry density，gas-filled porosity(saturation ratio) and anisotropic property. The computed results are in accordance with test data.
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Received: 05 February 2012
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2012, Vol. 31 
