Undrained shear strength of overconsolidated cohesive soil using modified rowe cell

The relationship between the undrained shear strength, su, and overconsolidation ratio, OCR, of clay material (kaolin clay) is important in order to estimate the material strength for preparing the ground model for small scale physical modeling test. In this study, the relationship between these parameters is determined using a modified Rowe cell equipped with a vane shear blade. Kaolin samples were prepared under different consolidation ratios and the unit weight of kaolin is measured using the modified Rowe cell device, while the undrained shear strength, su, was determined using the vane shear apparatus. It was found that the values of the consolidation ratio, CR, were inversely proportionate to su. A correlation between su and OCR was established based on the laboratory results and validated with several previous studies. In addition, a comparison was made between the developed equation and some existing equations from the literature. It was found that the proposed equation provide a close prediction to the previous laboratory results with a Root Mean Square Error less than 1.2. A difference arose due to the different types of clay used between previous and current studies. A positive relationship is established between the unit weight and OCR values for kaolin clay