K _o - OCR Relationships in Soil

The relationships between Ko and OCR are investigated for primary loading - unloading - reloading conditions. The study reviews laboratory data from over 170 different soils and presents an approach common to clays, silts and sands. Simple empirical methods for predicting Ko for normally consolidated and overconsolidated soils are evaluated. The validity of the methods is supported by statistical analyses. On the basis of the findings, only the effective stress friction angle (O') and prior stress history (OCR and OCRmax) are needed to predict approximate values of Ko.