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A Review of Hysteresis in Soil Physics

Discovery of Hysteresis in Soil Physics. In 1930 W.B. Haines showed that there is a strong hysteretic effect between the Soil moisture content q and the capillary pressure y.On the Right is a typical hysteresis loop. Water drains along the curve ABC, and re-wets the soil along a different curve CDA.He also was the first to postulate an explanation of why this might happen.Below is a capillary tube with a large pore at the centre with a different radius to the pore throat..

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A Review of Hysteresis in Soil Physics

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    1. A Review of Hysteresis in Soil Physics Denis Flynn Philip O’ Kane Alexei Pokrovskii

    3. The Independent Domain Theory The Independent domain model (IDM) was developed by Neel, Everett et. al. Poulovassilis was the first to apply it to capillary hysteresis. Advantages: allows prediction of ??-? relationship from a measured family of primary scanning curves. Integrating the density function f(ye,yf) over the whole area will give a total of 1.

    4. Application of the Independent Domain Model

    5. Mualem’s Model Mualem further simplified the independent domain theory. Modelling assumption: Introduced new notation: Can represent any scanning curve with this notation Where Advantages: Predicts ??-? relationship from the two outer drying and wetting curves.

    6. Further models Dependent domain theory. Parlange’s scaling procedure Advantages: Require now only one outer curve (preferably the main drying curve). Disadvantages: Require parameters for each inner scanning curve.

    7. Comparison with the Modern Preisach Model Summer 2003, Hugh McNamara and I applied the Preisach model to data sets supplied by R. Haverkamp. Our density required only one parameter. The fitting results were much improved over that of previous models.

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