Semi-analytical Wavefield Modelling for Pavement

This study presents an efficient semi-analytical wavefield modeling approach to generate surface wave dispersion spectrum for pavement-type structures. The method addresses the challenges posed by complex wave propagation through inversely dispersive medium, where the observed velocity spectrum often presents numerous mode branches. It computes theoretical dispersion curves, including real and leaky modes with complex wavenumbers by employing an eigenvalue-based higher-order thin layer method. Subsequently, the frequency domain dynamic surface responses are obtained to simulate in-situ pavement testing. The proposed approach is implemented on two pavement profiles: one representing an asphalt pavement model and the other a rigid concrete pavement model. The dispersion spectrum for the asphalt pavement has been validated against published numerical simulation. The study highlights that the fundamental antisymmetric mode of Lamb wave generated by the top layer dominates the wavefield. The overall dispersion trend can be utilized to estimate the properties of the top stiff layer. The low-frequency dispersion spectrum shows multiple modes corresponding to the base embedded layers underneath the surface layer. With the proposed wavefield modelling approach, the entire dispersion spectrum can be inverted to obtain the properties of the base course layers, eliminating the challenges to select specific modes.