Evaluation and Modelling of the Reconstituted Clays Considering Pre-peak Stiffness Degradation

Abstract

In this study, two clay samples, Kathmandu clay and Marine clay, were reconstituted with ordinary portland cement to study the stiffness degradation behaviour of cement mixed clay. Samples were prepared using 5%, 10% and 15% of cement to the mass of dry soil while other parameters were kept constant. The study reveals that cementation changes the strength and stiffness of the soils. The shear strength parameters of soil increase with the increase in cement content. Similarly, the initial stiffness of the clay increases with increase in cement content. Degradation of the stiffness during shearing is studied and simple equations for elastic modulus and modulus degradation of the cemented soils are proposed. Based on these relations, new stiffness degradation model is established and the predictability of the model is compared with the existing model. The comparison revealed that the prediction of the model is more accurate in determining the compression behaviour than the existing model for stiff clay.