The PM4Silt plasticity model was developed and implemented by Boulanger
and Ziotopoulou (2018) for representing low-plasticity silts and clays in geotechnical earthquake engineering applications. Model development emphasized approximating a range of undrained monotonic and cyclic loading responses of saturated low-plasticity silts and clays that exhibit stress-history normalized behaviors, as opposed to the responses of purely nonplastic silts and sands. PM4Silt is a stress-ratio and critical state controlled, bounding surface plasticity model that builds on the framework of the PM4Sand model.

PM4Silt: A silt plasticity model for earthquake engineering applications


  • effective stress
  • liquefaction
  • pore pressure
  • seismic loading


Boulanger, R. W., and Ziotopoulou, K. (2023). “PM4Silt (Version 2.1): A silt plasticity model for earthquake engineering applications.” Report No. UCD/CGM-23/02, Center for Geotechnical Modeling, Department of Civil and Environmental Engineering, University of California, Davis, CA. [February 2023; revised June 2023] [PDF available here]


UDM Version: 2.1
Release Date: Jun 12, 2023

Category: Low-Plasticity Silt and Clay

Software: Download: User Guide: Contact: Developer:

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