This paper models the road system as a three-layer structure comprising the surface course, base course, and frozen soil subgrade, investigating the dynamic response of the frozen soil subgrade under moving traffic loads. The surface and base courses are assumed to be single-phase elastic soils, and the subgrade is simulated as saturated frozen soil. First, each layer of the road system is deduced and solved by the Fourier integral transform. Then, by considering the load conditions of the vehicle on the road surface and the continuity conditions between layers, the dynamic response of the road system under the moving load of the vehicle is obtained. On this basis, the fast Fourier transform method is used to numerically calculate the dynamic response, and the influence of load, surface course, and subgrade parameters on the surface displacement is analyzed. The research results indicate that the vertical and horizontal displacement responses at the load center do not change significantly under different load movement speeds. The load frequency exhibits a low-frequency strong sensitivity and high-frequency weak sensitivity response pattern on the displacement response of the frozen soil subgrade surface. Changes in the modulus and thickness of the surface course significantly affect surface displacement. As the contact parameter increases, the peak vertical displacement of the road surface decreases, while the peak horizontal displacement gradually increases. The variation in displacement amplitude under high-porosity conditions is significantly smaller than that under low-porosity conditions.
Ma et al. (Fri,) studied this question.