Spectral analysis of a railway track in contact with a multilayered poroviscoelastic soil subjected to a harmonic moving load

• We study the effect of a moving load on a track–multilayered porous ground system.
• We analyse the shading representation of the unit spectral response.
• We determine critical ranges for the load speed for specific load frequencies.
• We determine critical ranges for the load frequency for specific load speeds.

The paper proposes an alternative approach to dispersion curves to analyse resonant phenomena in the context of wave propagation induced by a harmonic load moving over a railway track coupled to a multilayered poroviscoelastic medium. It consists of a shading representation of the spectral response in the frequency–wavenumber domain. Unlike the usual dispersion curves, it can take into account both the damping and the coupled system. Specific attention is paid to the first mode contribution. Critical ranges are determined from this shading representation: (i) for the load frequency when the load moves at a fixed constant speed, and (ii) for the load speed when the load frequency is constant. Both sub-Rayleigh and super-Rayleigh regimes are studied.