Factorial Numerical Analysis of Flexible Pavement Foundations with Emphasis on Groundwater Table Effect: Fid-Bau Portal

Factorial Numerical Analysis of Flexible Pavement Foundations with Emphasis on Groundwater Table Effect

Saad, Bassam

The presence of groundwater table (GWT) within a flexible pavement can have a pronounced detrimental effect on the mechanical response of its foundations and consequently on the structural performance of the pavement system as a whole. The related literature reveals that little work was done to rigorously model the impact of shallow GWT on the pavement's structural performance and investigate the sensitivity of this impact to the foundation's stiffness. In this paper, statistical factorial analyses were applied to numerical modeling to investigate the effects of GWT, foundations stiffness, and GWT-foundation stiffness interaction factors on the rutting of flexible pavements. A finite element model simulating the pavement foundations as nonlinear porous media governed by the Biot coupled behavior was set up first. The response of the model was evaluated for combination of design values of the GWT and foundation stiffness parameters each of which was defined at lower and upper levels (two levels-factorial design of experiments). Analysis of variance (ANOVA) method was then used to examine the effects of the factors analyzed on the pavement rutting. The analysis results showed that the GWT and its interaction effect with subgrade stiffness have significant influences on the pavement rutting. The detrimental effect of the GWT becomes more pronounced when the subgrade stiffness decreases, while such effect changes insignificantly with changing the stiffness of the granular base. The paper opens a new window for assessing the structural performance of flexible pavements under various GWT and foundation material conditions using the coupled finite element method in conjunction with the statistical factorial analysis approach.