Influence of Nonlinearity on the Stress Distribution in the Soil—Application to Road Engineering Problems

Abstract

The Boussinesq theory for the distribution of stresses in a half-space resulting from surface loads is largely used in road engineering. It is based on the assumption of linear-elastic homogeneous isotropic half-space for the soil media. Since the soil exhibits nonlinear and irreversible behavior, it is of major interest to study the validity of this theory for nonlinear response of soils. This paper investigates this issue by comparing the elastic stress distribution to that obtained using respectively nonlinear elastic and elastoplastic finite difference analyses. Results show that nonlinear elasticity does not influence significantly the stress distribution while plasticity reduces the attenuation of the vertical stress in the soil mass, which means that Boussinesq solution underestimates the stresses in an area which contributes to the soil settlement. An important discrepancy is also observed in horizontal stress for the case of homogeneous and multilayered soil when plasticity is considered.