YIELDING AND POST-YIELDING BEHAVIOUR AND MODELLING OF FIBRE-REINFORCED CEMENT-TREATED CLAY

Abstract

The inclusion of fibre reinforcement in cement-admixed soil has gained much attention over the years due to its ability to impart ductility to an otherwise brittle soil-cement matrix. The current study explores the use of 6-mm long polypropylene fibres as mechanical reinforcement in cement-treated Singapore marine clay. A series of drained and undrained triaxial tests were performed so as to investigate the constitutive behaviour of this material in terms of yielding and post-yielding behaviour, and destructuration characteristics. A three-yield point framework was introduced to describe its gradual yielding process. It was observed that the size and shape evolution of the yield locus was dependent on the pre-compression pressure, the degradation of the cementation bonds and the mobilisation of friction in the fibres. Finally, an energy-based constitutive model was proposed and validated against experimental data. The model generally showed good potential in predicting the stress-strain behaviour of fibre-reinforced cement-treated clay.