Sensitivity Analysis of Fine-Scale Parameters in Triaxial Tests of Soil Particles Based on Discrete Elements

In engineering, the deformation and uneven settlement of soil particles can easily lead to the damage of engineering foundations. Therefore, it is necessary to conduct microscopic experiments to investigate the properties of soil particle materials. By establishing a Discrete Element Method (DEM) model, the stress–strain and strength characteristics of soil particles with different compositions are analyzed in triaxial tests. The results indicate that the peak strength of the simulated samples under different confining pressures is positively correlated with the friction coefficient and negatively correlated with the particle stiffness ratio and porosity. When the confining pressure is 300 kPa and the friction coefficient is 0.5, the stress–strain curve of the sample reaches its highest peak, which is 1095.6 kPa. The porosity has the greatest influence on the initial elastic modulus and strain softening characteristics of the numerical samples. When the porosity is 0.3, increasing the confining pressure from 200 to 300 kPa results in a decrease in the peak strength by 398.5 kPa. This study explores the sensitivity of soil parameters under triaxial compression and analyzes their impact on the macroscopic mechanical properties.