This paper reports on the dynamic response of highway subgrade under moving heavy truck in cold regions. Numerical simulations are performed in two stages. In the first stage, the moving heavy truck vibration, induced by road roughness, is calculated through a three-dimensional dynamic interaction model of heavy truck-pavement-subgrade, and the time-histories of nodal loads on the top of the base are calculated through this model. In the second stage, a two-dimensional dynamic finite element model of the base-subgrade-ground system is formulated, using the calculated nodal loads from the first stage as input. The dynamic response of the subgrade is validated by field measurements, and the effects of truck type, axle loading, running speed, and road roughness on the vertical dynamic stress in the unfrozen period and the spring thawing period are analyzed and discussed.
