Dynamic responses of a rough road comprising dry and saturated layers subjected to moving-vibratory elliptical traffic load: Insights from a GMM-based semi-analytical solution

This paper presents a novel semi-analytical solution to dynamic responses of road system under moving-vibratory traffic load. In the proposed solution, the road system is appropriately taken as a multilayered system composed of the asphalt layer, subgrade layer, shallow dry subsoil layer and the underlying saturated subsoil. The traffic load propagated from the tire is represented by a moving-vibratory elliptical uniform load to account for the effects of pavement roughness. Taking advantage of the basic solutions developed for the single dry layer and saturated layer based on Fourier transformation technique, the governing matrix function for the problem considered is assembled by the robust global matrix method (GMM), which comprehensively integrates the moving traffic load boundary condition, the continuity conditions between the different layers and the infinite depth condition of the half-space. The time-domain dynamic response is finally achieved by using the composite Gauss-Legendre integral method. The proposed solution is validated through comparing with well-established solutions. Extensive parametric analyses are performed to investigate the dynamic amplification effects of the traffic load on each layer. Particular attention is paid to explore the effects of stiffness and thickness of subgrade on the dynamic responses of the multilayered road system. The newly developed solution yields more reasonable dynamic responses of the road system under the traffic load, which provides a useful tool for dynamic design and assessment of road system.