Analysis of Hydrothermal Coupling Effect of Asphalt Pavement between Tunnels in Seasonally Frozen Area

Abstract

At present, research on the icing process of asphalt pavement between tunnels in seasonally frozen areas still relies on historical weather or laboratory simulation data to predict the occurrence of icing. However, these methods are time-consuming and the experimental data are discrete. In this article, according to the phase-change heat transfer, moisture migration, and stress-strain equations, the hydro-thermal-mechanical coupling models of asphalt pavement in seasonal frozen area under saturated water conditions were constructed through the secondary development of general finite element software. Additionally, an indoor icing experimental system was independently developed to verify the effectiveness of prediction model. The results show that the rutting plate temperatures of indoor experiment are close to the simulated results of prediction model. The influence level of ice-water phase transition on temperature field at the road surface becomes smaller as the water film freezes gradually, and the temperature change of road surface tends to be smooth after the water film is completely frozen. The moisture inside the SMA-13 subgrade surface section between the tunnels first freezes, then melts, and finally freezes again. The times when the ice content reaches maximum and minimum coincide with the times when the temperatures reach minimum and maximum. The stress variation amplitudes of the road surface and the top surface of the middle, lower, base, and sub-base layers are weakened in turn. The subgrade section between tunnels basically does not produce vertical displacements when the soil foundation is not subject to frost heave. Interestingly, the relatively obvious vertical displacements have occurred above soil foundation when the frost heave of soil foundation is considered, and the vertical displacement of the surface and base layers are relatively consistent. Therefore, the hydro-thermal-mechanical coupling models proposed in this article are effective for predicting the occurrence of icing for asphalt pavement.