Abstract: The erodibility of clay exhibits significant variability across different influencing factors. The existing research using compaction approach for specimen preparation neglected the non-uniformity in soil specimens and is unsuitable for high plasticity clay. In this study, the saturated preconsolidation approach was used to prepare uniform kaolinite specimens to simulate natural consolidating conditions. The prepared specimens were then analyzed using a hole erosion analyzer, and the surface morphology of the eroded hole was quantified using a 3D scanner. A total of 18 hole erosion tests were conducted under various preconsolidation pressures and erosion directions. The erosion resistances were found to increase with higher prestress, and the variation of critical shear stress across different erosion directions reached 29%. The SEM images reveal a stack-packing microstructure in the consolidated specimens, with a denser clay aggregate packing observed under higher pre-stress conditions. The anisotropic erosion property is properly described by the radial anisotropic coefficient κ_-r  and the roughness anisotropic coefficient κ_pr , and the critical shear stress τ_c  is negatively correlated with κ_-r  , while its correlation with κ_pr is not obvious.

Key words: cohesive soil, erodibility, hole erosion test, anisotropy, microfabric