PFC3D Particle Flow Simulation of Nano-Clay Modified Loess Triaxial Test

PFC3D software was used to study the influence of different nanomaterials, dosage, confining pressure, and dry density on the mechanical properties of improved loess, and determine the parameter relationship between macro and meso of improved loess. Through a numerical model of improved loess and a three-axis experiment, the stress-strain curve of improved loess was obtained. The results of the numerical simulation were compared with the results of indoor experiments, and the shear strength index of improved loess was consistent. The experimental results showed that: (1) When the confining pressure is constant, the deviatoric stress of the improved loess sample increases with the increase of nano-clay content. The stress and strain of the improved loess are positively correlated. When the confining pressure is different, it shows a softening type and a strong hardening type. (2) When the content of attapulgite is less than 2%, the shear strength obtained by numerical simulation is generally lower than that derived from laboratory tests; conversely, when the content exceeds 2%, the situation is reversed. (3) When the content of nano-montmorillonite modified loess in numerical test samples is less than or equal to 4%, the shear strength obtained through numerical simulation is higher than that measured in laboratory tests; conversely, when the content exceeds 4%, the situation is reversed.