PM4Sand

PM4Sand and PM4Silt: Constitutive Models for Nonlinear Dynamic Analyses

May 12-13, 2025

Alpha Gamma Rho Hall, Walter A. Buehler Alumni Center, University of California, Davis

Registration open now here

Overview: 

This two-day short course will cover the constitutive models PM4Sand and PM4Silt and their use in nonlinear dynamic analyses of liquefaction and cyclic softening during earthquakes. The PM4Sand and PM4Silt models are stress ratio-controlled, critical state-compatible, bounding surface plasticity constitutive models developed by Boulanger and Ziotopoulou over the past decade for earthquake engineering applications. They are implemented as user-defined dynamic link libraries for use in Itasca's FLAC2D program.

The topics to be covered include: background and formulation of PM4Sand and PM4Silt; calibration procedures for engineering applications (single element simulations of various loading paths; capabilities and limitations) for both models; hands-on calibration exercises; challenges and lessons learnt from certain calibrations; and a general discussion on the need for the element-level calibrations and system-level analyses to be informing each other.

This course is geared toward participants already having some level of familiarity with nonlinear dynamic analyses, nonlinear constitutive models, soil liquefaction and cyclic softening during earthquakes, and the computer program FLAC/FLAC2D. Coverage of each topic will include a review of background information and underlying fundamentals, but the focus will be more on details and procedures important to using these numerical models in practice. Participants will be expected to bring a laptop computer loaded with FLAC2D 9.0 (a trial version will be sufficient), the PM4Sand Version 3.3 and PM4Silt Version 2.1 dynamic link libraries, and the calibration drivers for PM4Sand (pm4sand.engr.ucdavis.edu/) and PM4Silt (pm4silt.engr.ucdavis.edu/) so they can participate in the example exercises. Users of FLAC8.1 will be able to follow along, but the examples will be presented using the newer FLAC2D. Participants will be provided with additional background materials for review prior to the course.

Instructors:

Ross W. Boulanger, PhD, PE, NAE and Katerina Ziotopoulou, PhD, PE

For questions, please email Katerina (kziotopoulou at ucdavis.edu).

Tentative Agenda:

Day 1: PM4Sand

Day 2: PM4Silt