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Exponential model

This model provides a simple, single-parameter exponential function to describe the soil-water retention curve, as presented in a study by Abed and Sołowski (2017)1. Its simplicity is advantageous when detailed experimental data is unavailable or for preliminary analyses. The numgeo keyword reads:

*Hydraulic = Exponential [, Swr = ]
zeta

The material parameters of the van Genuchten model are given in the following.

  • \(\zeta\) is a fitting parameter with units of inverse pressure (e.g., kPa\(^{-1}\)) that controls the rate of desaturation. A higher value of \(\zeta\) results in a steeper drop in saturation as suction increases.
  • \(S^{wr}\) (optional) is the residual degree of saturation (-).

  1. Ayman A. Abed and Wojciech T. Sołowski. A study on how to couple thermo-hydro-mechanical behaviour of unsaturated soils: physical equations, numerical implementation and examples. Computers and Geotechnics, 92:132–155, 2017. doi:10.1016/j.compgeo.2017.07.021. ↩