Effect of hydraulic anisotropy on soil-water characteristic curve

The effect of hydraulic anisotropy on soil-water characteristic curve (SWCC) has not been investigated. Experiments and numerical modeling were carried out on compacted specimens with different initial conditions. In the hydraulic experiments including drying SWCC and saturated permeability tests, horizontal-layering (HL) and vertical-layering (VL) specimens were prepared from statically compacted homogeneous sand-kaolin samples with various initial conditions. Tests on these specimens were then modeled numerically using GeoStudio Software (2007) of SEEP/W combined with Air/W package. The results from both laboratory experiments and numerical modeling were in good agreement. SWCC was found to be independent of hydraulic anisotropy. The difference was observed in equalization time during application of matric suction larger than the air-entry value of the specimens. HL specimens have a longer equalization time compared to VL specimens, and the difference has a ratio similar to the hydraulic anisotropy of the soil.