Consideration of the Non-Linearity of Unbound Granular Materials in the Design of Flexible Pavement Structures in Senegal

Abstract

The design of road structures in Senegal is based on the assumption of linear elastic behavior of the materials making up the various pavement layers. However, studies have shown that the experimental behavior of granular materials is rather nonlinear elastoplastic and is characterized by the reversible modulus M r which depends on the state of stress. In this article, the study of nonlinearity was investigated with a view to its possible consideration in the design of flexible pavement structures. The results showed that the strains and stresses found are higher in the nonlinear case than in the linear case. Compared with the results obtained with the nonlinear model integrated into Alizé LCPC, the k-Ө model tends to overestimate vertical stresses and strains in sub-base layers. For subgrade layers, however, Alizé LCPC seems to overestimate them. These variations could be explained by discontinuities at layer interfaces and variations in the stiffness of materials in the pavement. However, the validation of nonlinear calculations with a view to improving road design in Senegal remains to be verified, in particular by experimental data.