Fredlund 2-Point (2008) Estimation

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The ksat is the value of the specified saturated hydraulic conductivity.



The AEV field shows the air-entry value as calculated based on the estimated curve.



The Slope is the maximum slope (on a semi-log scale) as calculated based on the estimation curve.


k minimum:

The value entered in this field represents the minimum allowable hydraulic conductivity. The minimum hydraulic conductivity should correspond to conditions encountered as the soil approaches residual conditions. A value of 1e-14 m/s is typical of the point where vapour flow begins to dominates flow. A minimum hydraulic conductivity is less than 1e-10 m/s may significantly increase the number of nodes used to obtain a solution. It is suggested that a minimum value of 1e-10 m/s be entered for most practical problems.


Apply k minimum:

The equation presented by Fredlund 2-Point (2008) did not have a limitation on the minimum allowable hydraulic conductivity. Applying a reasonable minimum to the unsaturated portion of the curve and dramatically improve numerical computations.



The Residual WC field refers to the calculated residual hydraulic conductivity.



The Estimate button is provided at the bottom of the dialog in order to allow the user to estimate the hydraulic conductivity.



The Graph button allows the user to display a graph of suction versus hydraulic conductivity. The interpolated curve will also be displayed. It should be noted that laboratory data will be interpolated on an arithmetic scale.