Dynamic responses of transversely isotropic and layered elastic media with imperfect interfaces under moving loads

Flexible pavement is widely used in engineering practice but is often subjected to the moving traffic loads, with imperfect contact behavior at the interfaces between adjacent layers. This study investigates transversely isotropic and layered elastic media with imperfect interfaces under moving vertical and horizontal loads using a semi-analytical method. The governing equation for moving loads is established within a Cartesian coordinate system and by virtue of the Galilean transformation, which is further decoupled into two ordinary differential equations in terms of the powerful Cartesian system of vector functions. General solutions for any layer are obtained, and the dual-variable position method is applied to derive the semi-analytical solutions for the layered pavement in the vector function domain. The lately introduced refined conversion algorithm, originally from the discrete convolution-fast Fourier transform (DC-FFT) algorithm, is applied to obtain the solution in the physical domain, which can efficiently remove the Gibbs effect near the source. The solutions are validated by comparison with existing solutions and numerical examples are presented to study the effect of interface modulus, moving load velocity, Young’s modulus of asphalt concrete and horizontal/vertical loading ratio on the surface dynamic response of the flexible pavement. Finally, the fatigue and rutting life of the pavement structures corresponding to different imperfect interface moduli are analyzed. The present solution provides practical guidance for the design of flexible pavement.