DEM analyses of true triaxial and wetting tests on unsaturated structural loess

Abstract

The discrete element analysis of the true triaxial and wetting tests is conducted to study the macroscopic and microscopic mechanical properties of unsaturated structural loess under complex stress states. The change of axial strain after wetting and the variation of void ratio and bond breakage number with water content were studied in this work. The results show that the collapsing failure occurs when the deviatoric stress approaches or exceeds the peak shear strength of the corresponding saturated structural loess sample. There is little difference in the axial strain between the quick wetting (QW) method and gradual wetting(GW) method, and the volumetric strain of the samples wetted by QW are larger than that by GW specimen. The bond breakage number of the samples wetted by QW are slightly higher than that by GW. However, the number of bond breakage wetted by the two wetting methods is slightly higher than that of the corresponding saturated structural loess sample.