Geomechanics and Geotechnics


Hypoplastic interface model

Frictional interface model for granular soils based on Hypoplasticity using the hypoplastic UMAT Implementation from the webpage. 

Download under GNU licence: Implementation by: Henning Stutz

FRIC and short documentation 

Please refer to the following literature using the model

  • Stutz, H., Mašín, D., Sattari, A. and Wuttke, F. (2017). A general approach to model interfaces using existing soil constitutive models - application to hypoplasticity. Computers and Geotechnics , Volume 87, July 2017, Pages 115-127 (doi: 10.1016/j.compgeo.2017.02.010).
  • Stutz, H., Mašín, D. and Wuttke, F. (2016)  "Enhancement of a hypoplastic model for granular soil-structure interface behaviour", Acta Geotechnica 11, No. 6, 1249-1261.

When using implementations from in your research, please cite it asG. Gudehus, A. Amorosi, A. Gens, I. Herle, D. Kolymbas, D. Mašín, D. Muir Wood, R. Nova, A. Niemunis, M. Pastor, C. Tamagnini, and G. Viggiani. The project. International Journal for Numerical and Analytical Methods in Geomechanics, 32(12):1571-1572, 2008.

Hysteresis in Soil-Water Retention Curves

In order to determine soil-water retention (SWR) behavior of not-plastic particulate medium, the invading pressure in inter-particle level is correlated to the governing effective pore area in wetting and drying paths. In a drying path, the air-entry pressure (AEP) of a pore throat, where the area of a cavity is minimum, with numerically solving the Young-Laplace curvature equation using the finite difference method and Newton-Raphson (Jacobian) approximation technique is determined. Similarly, the water-entry pressure (WEP) is correlated to a maximum area of cavity.

Download files


  • Sattari, A.S., Siebeliest, M., Toker, N.K. and Wuttke, F. (2019). Simulation of Hysteresis in Soil-Water Retention with a Correlation Between the Invading Pressure to the Governing Effective Flow Area. Granular Matter Journal. (Revision Process)

  • Sattari, A. S. and Toker, N.K. (2016). Obtaining Soil-Water Characteristic Curves by Numerical Modeling of Drainage in Particulate Media. Computers and Geotechnics Journal, Vol. 74, 196-210.