Influence of differential settlement on pavement structure in expressway widening project

In order to decrease the differential settlement at the connection of old and new subgrade, this paper studies the mechanical influence of differential settlement on pavement structure between the old embankment and the new one in expressway widening project with the ANSYS analysis. By calculating stress in bituminous pavement, the trait of accessional stress and destructive styles in different periods of useful life are analyzed, and the position of longitudinal crack is forecasted. The research results show that, in early cracking, the bigger tensile stress appears on the top of surface and base, and the cracking position is closer to the center of the old road when the maximal tensile stress is further away from the bonded areas between the old and the new embankment; in the later cracking, the maximal flexural tensile stress appears on the top of asphalt surface and the maximal tensile stress appears at the bonded areas nearby. When the biggest differential settlement is more than 1.5 cm, the additional stress in bituminous pavement will be bigger than its confessional tensile stress, the cracks will occur at here.