Influence analysis of the selection of foundation model on fatigue stress evaluation results of cement concrete pavement-based on GPR and FWD

This study showed a method of selecting appropriate foundation models for fatigue stress analysis of cement concrete pavement. Based on the strength and damage conditions of the base and the correlation between the crack rate of the base (C-b) and modulus of the base (E-t), the integrity and stiffness of the base were evaluated. Moreover, the applicability of the base to the Winkler foundation model and the elastic half-space foundation model for each road section was clarified based on the evaluation results. The cement concrete pavement's load stresses and temperature stresses under different technical conditions were calculated by combining the parameters of the thickness of the cement concrete surface layer (h(c)), modulus of the cement concrete surface layer (E-c), and Et of each road section and the compatible foundation models. The effects of the changes of parameters h(c), E-c, and Et on the load and temperature stresses of cement concrete surface layers under different foundation models were also investigated. It was observed that the effects of E-c and Et on the temperature stresses of the cement concrete surface layer are more pronounced compared to h(c). h(c) is the parameter that has the most significant influence on the internal load stress of the cement concrete surface layer. The Winkler foundation model is more sensitive to the change in hc, and the Elastic half-space foundation model is more sensitive to the change of E-c and Et. No matter what kind of technical condition the pavement is and what type of foundation model is adopted, the influence degree of each structural parameter on the load stress of the cement concrete surface layer is not different obviously, and the influence ratio is relatively stable. However, for the temperature stress, under different pavement technical conditions, the changing amplitude of temperature stress caused by the changes of h(c), E-c, and Et is significantly different, and the greater the h(c) is, the greater the influence of the changes of h(c), E-c, and Et on the temperature stress is.