Shakedown Analysis of Flexible Pavement on Saturated Subgrade Under Moving Traffic Loading

In this paper, the shakedown behavior of flexible pavement on saturated subsoil subjected to moving vehicle loading is studied. Based on Biot’s dynamic theory of saturated porous media, dynamic stresses of layered saturated subgrade are derived by the transfer matrix method. Then, the lower limit shakedown theory is introduced to estimate the shakedown state of the pavement system. The study focuses on the effects of vehicle’s velocity, saturated soil’s permeability, pavement and subsoil’s strength and modulus ratios on the shakedown behavior. Theoretical results show that for the pavement system on the saturated subgrade, the growth of stiffness ratio or strength ratio leads to the transition of the critical shakedown state from the upper to the lower layers. It is also found that there exists a set of optimal modulus and strength ratios so that the upper and lower layers can reach the critical shakedown state simultaneously.