Modeling triaxial tests on alluvial sand and analyzing soil's shear strength parameters with DEM

Abstract

Abstract The discrete element method (DEM) has proved to be a valuable tool in understanding the mechanisms of soil friction mobilization and compressibility, Many problems, such as particle breakage and erosion, can be better understood using DEM. The article uses DEM to simulate the results of triaxial tests performed on alluvial sand. Developing new routines and implementing them in a former DEM code made it possible to perform triaxial test simulations without using additional material to represent the rubber membrane, making triaxial test modeling by DEM less complex and more accurate. Predicted and experimental results presented good adherence, and classical works from literature corroborated the variation of the macroscopic friction angle with soil porosity in the modeling. The friction angle between particles was close to that obtained between two adjacent quartz particles (main sand component), 26°, highlighting the result's consistency. Furthermore, samples tended to expand under lower confinement stress and compress for higher confinements for the same porosity. The model evaluation proved that it renders results of the sand's mechanical behavior under varying internal friction angle, porosity, and particle size that are coherent with the vast experimental evidence in the geotechnical field. The obtained results illustrate the model's potential for use in geotechnical problems, mainly in the case of settlement predictions under shearing, where volumetric soil strains play an essential role.

Keywords

• numerical simulation
• discrete element method
• triaxial test
• alluvial sand
• shear strength
• volumetric strain
• soil mechanics