Shakedown of layered pavements under repeated moving loads

In recent years, shakedown theory has been suggested as a more rational theoretical foundation for pavement structural design. This paper suggests a numerical approach to find shakedown load limit of layered pavements based on an investigation of residual stress field, which plays an important role in helping the structure to reach the shakedown status. A finite element model is established for pavement structures under repeated moving surface loads, where the Mohr-Coulomb yield criterion with associated plastic flow is assumed to capture the plastic behaviour of pavement materials. A criterion based on static shakedown theorem is suggested to distinguish shakedown and non-shakedown status of pavement structures subjected to different magnitudes of loads, thereby achieving a numerical shakedown limit. Comparisons between the numerical shakedown limits and theoretical shakedown limits of Wang and Yu (2013a) show good agreement. Investigation of the development of residual stresses in layered pavements also provides deep insight to the application of shakedown theory. In addition, the proposed approach can be easily extended to pavement materials following non-associated plastic flow rule.