Abstract:The dynamic response of a subgrade-slab system subjected to harmonic strip moving load is investigated using the Fourier transform and the inverse Fourier transform. The subgrade-slab interaction is considered,and the pavement is treated as orthotropic elastic slab resting on a double-layered subgrade. Taking the soil layer above the groundwater table as elastic single-phase layer and the soil layer below the groundwater table as saturated medium,the governing equations of subgrade-slab system are solved in the transformed field domains of moving space considering the finite depth of layers,and Lame decomposition theorem of displacement field and potential functions. Considering the mixed boundary condition at the upper surface,the fixed boundary condition at the lowest surface and that the stress and displacement at the interface of the layers are continuous;analytical solutions of vertical displacement,stress and pore water pressure in saturated layer are derived using the Fourier transform and the inverse Fourier transform. Numerical results are obtained by using the inverse fast Fourier transform(IFFT). Calculation results show that the vertical displacement of soil medium is considerably affected by the moving load velocity,frequency and the permeability of saturated layer. The influence of depth of elastic single-phase layer on vertical displacement depends on moving load velocity. The depth of elastic soil layer has great effect on pore water pressure in saturated layer,and the influence of the rigidity ratio between elastic single-phase layer and saturated layer on pore water pressure is similar to that of the depth of elastic soil.