Dynamic response of the 3D pavement-transversely isotropic poroelastic ground system to a rectangular moving load

A semi-analytical approach is applied to investigate three-dimensional (3D) vibration in a coupled pavement and ground system subjected to a rectangular moving load. The pavement is simplified as an infinitely long orthogonal anisotropic elastic plate, and the ground materials are assumed to be multi-layered and transversely isotropic soils obeying the conditions of Biot's dynamic poroelastic theory. The governing equations of the system are solved using the double Fourier transform, and the fast Fourier transform is used to obtain the dynamic responses in the time domain. The results show that the dynamic responses are significantly affected by the load velocity and peak or dip at the critical velocity. The variation in the dynamic response with depth as calculated by the transversely isotropic model is similar to that calculated with an isotropic model, but is significantly influenced by modulus anisotropy and soil layering. If EH < Ev or Gv < C66, the subgrade design based on dynamic deformation control method will be unsafe when subjected to high load velocity. Instead, this calculation model for a subgrade is more appropriate for practical applications because of its incorporation of transverse isotropy.