Dynamic response of unsaturated poroelastic ground underlying uneven pavement subjected to vehicle load

In this study, the dynamic response of unsaturated ground coupled with an uneven model due to vehicle load is investigated. The governing equation of the unsaturated poroelastic ground is established by extending Biot's theory. The uneven pavement is simplified as a Kirchhoff small-deflection thin plate. The vehicle is modeled as a spring–mass damping system, while considering the effect of the uneven pavement. The dynamic wheel-uneven pavement force is calculated by regarding the pavement roughness as a sinusoidal wave. The solutions in the wavelength domain are presented by applying a double Fourier transform. Subsequently, the corresponding numerical results in the space domain are obtained by employing the numerical method of the double inverse Fourier transform. Next, the stress paths of the unsaturated soil element caused by the vehicle load are calculated and analyzed. The numerical results show that the additional dynamic load caused by the uneven pavement is affected by pavement roughness and vehicle velocity. The increasing vehicle velocity slightly affects the vertical normal stress, shear stress, and stress path. However, the peaks of the horizontal normal stresses increase, and the vertical displacement decreases. The ground dynamic response is significantly and positively correlated with the axle load. As saturation increases, the vertical displacement and dynamic stresses of the ground soil decrease slightly, and the stress path is reduced.