Climate warming leads to the aggravation of infrastructures and environmental risks in permafrost regions. There are few reports about the interaction between airport runway and permafrost foundation. Based on long term field monitoring, remote sensing and comparative analysis approaches, our study quantitatively investigates the impacts of runway and climate on permafrost in northernmost China, and also the engineering problems are analyzed. Results show that the atmospheric inversion in winter controls the regional permafrost distribution in the study area. Ground surface warmed significantly after vegetation removal because of the runway construction. The maximum temperature difference among the forest, the swamp and the bared gravel can reach to 30 degrees C in summer. Such surface alterations caused abnormally rapid degradation of permafrost within the context of climate warming. The rate of permafrost table deepening varies from 0.461 to 0.590 m/a over the 2007-2017 periods. Also, the annual mean ground temperature at the 13 m depth increased at a rate of 0.054-0.130 degrees C /a. Its annual increase value is 0 similar to 0.47 degrees C with an average 0.108 +/- 0.124 degrees C. In turn, permafrost degradation caused runway safety problems, such as the decrease of bearing capacity, increase of longitudinal slope, decrease of planeness, pavement cracks, density decrease of the foundation and cement concrete pavement cavity. However, in the natural places, the permafrost remained relatively stable and didn't show a continued degradation trend. The permafrost table fluctuated with air temperature changes. Its interannual fluctuation range is 0 similar to 0.25 m, with an average 0.08 +/- 0.08 m. The interannual fluctuation range of ground temperature at the depth of 13 m is 0.01 similar to 0.10 degrees C, with an average 0.06 +/- 0.03 degrees C. In addition, the zero curtain phenomena were observed at the study site. Once the zero curtain periods were over, the ground temperature warmed rapidly. These findings have positive implication for new runway design in permafrost regions.

Mobei Highway is the first expressway in permafrost regions in China. It is located in Mohe County, northeast China. It is cold and snowy in winter in this area. A recorded lowest temperature reached -52.3°C in 1969. The engineering geological conditions are complicated and constructions are faced with permafrost, icing and frost penetrations. According to the results of the exploration the properties and distribution of permafrost and engineering geological characteristics were analyzed. Two design ideas of permafrost protection and the permafrost excavation were proposed and adopted during the construction. A high embankment and reinforcement measures were used to protect permafrost and stabilize the embankment. A synchronous sealing technique was adopted in road construction, which could prevent surface water from infiltrating into embankment and make it comfortable when driving on the white cement concrete pavement. Also, anti-frost cement was used to improve the adaptability and life of the pavement and its white color can decrease the intake of solar radiation heat in cold regions.