The application of a three-surface kinematic hardening model to repeated loading of thinly surfaced pavements

Abstract

This paper examines the application of kinematic hardening to modelling the behaviour of thinly surfaced pavements dominated by the clay subgrade. An existing three-surface kinematic hardening model has been found to predict too much shear strain and therefore too much settlement under repeated loading for certain stress conditions. Under some stress conditions, the model also predicts an accumulation of negative shear strain with increasing number of cycles of load, leading to a pavement rut depth which decreases with increasing numbers of cycles. Consequently, a new model has been developed by modifying the flow rule and hardening modulus. The new model requires 10 parameters, most of which can be determined directly from simple triaxial tests. The new model is validated against drained cyclic triaxial results in order to determine model parameters, and it is shown that the new model predicts better the accumulation of shear strain and the problem of accumulation of negative shear strain is eliminated. This new model is applied to the repeated loading of a thinly surfaced pavement and is seen to predict realistic resilient and permanent deformations.