Abstract:
For modeling gas transport in soils and other porous media is necessary to know the diffusion coefficient. Gas diffusion
in soil is a dominant process when convective transport is minimal. Gas molecules from soil are constantly moving as
the kinetic theory of gases. Soil compaction has a major impact on gas transport characteristics. Over the years many
models have been developed for determining the gas diffusion coefficient in soil, defined as the ratio of gas diffusion in
soil (D) and the gas in the air (D0). Millington and Quirk (1960) and Moldrup (1999) determined the variation of
diffusion coefficient for different soil types, based on Penmann’s numerical and empirical models(1940). Diffusion
models tend to perform better in some soils than in others. Knowledge of the diffusion coefficient is essential for
developing accurate predictive models for gas transport in porous media and to improve our understanding of the basic
processes involved in transport. Gas diffusion measurements on different samples of different sizes is an important goal
in research diffusion. In this context, based on experimental research and extensive bibliographical studies, the authors
determined the relationship between the soil suction curve and moisture. Suction curve was used to estimate the
permeability of which is subsequently used in modeling the behavior of soil. Nowadays, significant contributions were
made by researchers in determining and measuring suction curve. However, almost all measurement models of suction
have deficiency, including such aspects as reliability, cost, method of application and practicality. Therfore, there is still
a need for improved techniques for measuring suction
