To maintain the temperature and settlement stability of a subgrade, a combination of graded crushed rock layer and insulation layer may be applied to optimize pavement structures. This study verifies a proposed numerical model of pavement and subgrade design in permafrost regions and evaluates temperature and settlement characteristics at different particle size and thickness of graded crushed rock layer and different thickness and location of insulation layer. The results show that the temperature and settlement of the combination of graded crushed-rock layer and insulation layer decrease significantly as the particle diameter and thickness of graded crushed-rock layer increase, and vary little when the thickness of insulation layer is more than 0.15 m. The location of installation layer has significant influence on the temperature of the subbase layer, but has little influence on the temperature of the subgrade. The maximum settlement of the pavement structure and subgrade decreases when the installation layer varies from the top of the subbase layer to the bottom of the subbase layer. The optimal combination of graded crushed-rock layer and insulation layer is that the 0.15 m-thickness installation layer is at the bottom of the 0.50 m-thickness graded crushed-rock layer with the particle size of 6–8 cm. This study provides a theoretical basis for the design, construction, operation, maintenance, and safety management of airport runways in permafrost regions.

The settlement in permafrost regions has a significant effect on the safety of the aircraft. Therefore, a numerical model of asphalt concrete pavement and subgrade in permafrost regions is proposed and verified by comparing with previous studies. Numerical models under the dynamic load of aircraft are used to analyze the settlement nephogram, time-dependent curve, and settlement curve. Results show that the influences of different parameters on settlements decrease slowly at the depth of 0–1.45m, then decrease quickly at the depth of 1.45-2m, finally tend to be stable. The peaks of settlements increase with the growth of international roughness index, taxiing speed, and aircraft’s weight. The settlement increases little when the international roughness index is more than 3. The settlement varies significantly when the taxiing speed is from 30m/s to 70m/s. The study provides a theoretical basis for the construction and maintenance of asphalt concrete pavement and subgrade in permafrost.