Wetting effect on CBR properties of compacted fine-grained residual soils

Fine-grained residual soils are widely used as compacted fill materials, although they are well known to be vulnerable to weakening when wetted, leading to fill slope failures. A practical approach to evaluate this wetting effect based on typically available properties is being developed. Extensive evaluations of laboratory-compacted soils and variability of field-compacted soils, followed by the development of a simple deformation-based stability model, are reported. The wetting effect is represented by the CBR soaked to unsoaked ratio, and the soil activity can be used as a predictor of this ratio. Compaction effort has a significant effect on this ratio. Effects of variability of compacted soils and uncertainty of prediction equation are incorporated into the stability model to evaluate the wetting effect on slope probability of failure.