Journal Title

Journal of Geotechnical and Geoenvironmental Engineering

Publication Date



A discrete-element method (DEM) assembly of virtual particles is calibrated to approximate the behavior of a natural sand in undrained loading. The particles are octahedral, bumpy clusters of spheres that are compacted into assemblies of different densities. The contact modelis a Jäger generalization of the Hertz contact, which yields a small-strain shear modulus that is proportional to the square root of confining stress. Simulations made of triaxial extension and compression loading conditions and of simple shear produce behaviors that are similar to sand. Undrained cyclic shearing simulations are performed with nonuniform amplitudes of shearing pulses and with 24 irregular seismic shearing sequences. A methodology is proposed for quantifying the severities of such irregular shearing records, allowing the 24 sequences to be ranked in severity. The relative severities of the 24 seismic sequences show an anomalous dependence on sampling density. Four scalar measures are proposed for predicting the severity of a particular loading sequence. A stress-based scalar measure shows superior efficiency in predicting initial liquefaction and pore pressure rise.

Author Supplied Keywords

Liquefaction, Discrete-element method (DEM), Contact mechanics, Simulation, Undrained loading


Civil engineering; Discrete element method; Granular materials--Fluid dynamics; Simulation methods; Soil liquefaction

Publication Information

Journal of Geotechnical and Geoenvironmental Engineering, 2014, Volume 40, Issue 12, 1-13.

© 2014 American Society of Civil Engineers.

Linked version is the final published version.





Document Type

Journal Article

Published Version

(Available to UP community as permitted)

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Engineering Commons