Clay soil is known to create many problems in civil engineering works specifically from the design, construction and maintenance stages. Special consideration should be taken especially in the design of infrastructures on clay soil. Over consolidation ratio (OCR) and the undrained shear strength (Su) of clay soil is very important in the field of Geotechnical engineering as it can be used to estimate the behavior of clay. In this study, a relationship between undrained shear strength and over consolidation ratio (OCR) parameters was found to establish a non-linear correlation formula. Laboratory experiment was done by taking undisturbed samples at different depths of 0.5 m from 1.0m to 3.5m below ground level. The samples were then tested under the odometer and vane shear test to obtain the OCR values and the undrained shear strength (Su) respectively. It was found that the OCR and shear strength values are inversely proportional at similar depths and at the same undrained conditions. The OCR value however, decreases when the soil strength increases. An acceptable correlation was obtained from the relationships where the R2 values were very close to 1.0 using polynomial equations. The comparison between the experimental result and previous researchers produced a non-linear correlation that shows a similar pattern with this study.
Keywords: Clay, Over-consolidation ratio, Undrained shear strengt
