LS-DEM Guided Analysis of Geotechnical Tests: Exploring Strength Anisotropy and Stress Dependency

Abstract

Reliable interpretation of model tests in geotechnical engineering often is hampered by the limitations of traditional laboratory element testing, especially under low-stress conditions and unconventional stress paths. This paper presents a pragmatic hierarchical multiscale numerical approach that combines the level set discrete-element method (LS-DEM) and continuum-based analysis to improve the interpretation of scaled geotechnical tests. LS-DEM enables high-fidelity simulations of soil behavior, overcoming challenges such as boundary effects and metrological limitations that make accurate assessments under specific conditions in standard laboratory tests difficult. The virtual LS-DEM specimens can be calibrated reliably using traditional laboratory tests, such as oedometer and triaxial tests. This approach was demonstrated and implicitly validated through its application to a study of displacement-dependent earth pressure on retaining walls. Key findings include the identification of additional kinematic constraints under plane strain conditions as the primary factor behind the high peak strength observed in scaled tests, and the observation that the strength of granular materials is negligibly affected by changes in stress level. In addition, the observation of pressure-dependent elastic parameter trends, consistent with previous studies, further validates LS-DEM as a reliable tool for quantitatively capturing the behavior of granular materials. By reducing reliance on semiempirical scaling laws and providing a robust framework for informing continuum-based models, this LS-DEM–based hierarchical approach effectively bridges the gap between small-scale laboratory experiments and large-scale geotechnical applications. Ultimately, this methodology enhances the design and analysis of geotechnical structures with greater confidence and accuracy, providing a practical and effective tool for addressing complex geotechnical engineering challenges.