ABSTRACT
A parametric study was conducted on flexible pavements using a two-dimensional explicit finite difference program – Fast Lagrangian Analysis of Continua (FLAC). The main objective of this study was to investigate the stress paths induced in unbound granular base and subbase courses by a moving wheel for summer and spring conditions. The simulations carried out with conventional elastic properties of each pavement material confirmed the development of significant tensile stresses at the bottom of each layer, which may not be always tolerated by the unbound aggregates if the apparent cohesion is too low. Adding the Mohr-Coulomb failure criterion in these materials was sufficient to modify the stress path in each element of the base and subbase layers. Principal stress direction rotation as the moving wheel approaches was illustrated using a simplified axi-symmetric domain. The parametric analysis established also that stress paths were strongly influenced by the failure characteristics of the unbound granular materials.
