Study On Impact Of Environmental Temperature Changes On Bearing Capacity Of Airport Runway In Permafrost Regions

At present,it is at the stage of major development of civil aviation.In the future,the civil aviation industry will enter a golden period.Due to climate and other reasons,permafrost region are mostly underdeveloped areas.As a transportation project,the airport can build an air bridge for people to communicate.The difficulty in the construction of the runway in the permafrost region is that the frozen soil is unstable and fluctuates due to temperature.The ambient temperature is undergoing changes,global warming has become the consensus of mankind.The distribution of permafrost is closely related to the ambient temperature,and the average annual temperature can indirectly represent the influence of geographical factors on permafrost.Therefore,with the help of simulation software,the change of runway bearing capacity caused by the degradation of the permafrost has been studied.The main work and achievements are as follows:1、Based on the theory of hydrothermal coupling,a calculation model for the geothermal field of the runway in permafrost region was established.The monthly variation of the runway and the law of yearly change within 30 years were studied.The law of ground temperature change was studied when measures such as soil replacement measures,gravel measures,and heat insulation plates were adopted.The cooling effect of combined measures and single measures were compared and analyzed.2、A simplified static model considering the effect of aircraft loading was established to study the influence of non-linear temperature distribution on pavement deformation.Monthly deformation of the runway within a year and yearly deformation within 30 years were studied.And the impact of measures such as soil refilling,gravel measures,and insulation board measures on deformation was analyzed.It was found that the low strength of the insulation board increases the deformation of the pavement.3、With the help of the seepage-stress coupling analysis module,the deformation model of the runway thaw in the permafrost region was established.It was found that the average annual temperature will affect the depth of melting of permafrost,and the melting depth controls the size of thawing deformation.A subroutine was used to establish the frost heave calculation model.The frost heaving deformation law at different annual average temperatures was simulated.4、The permafrost region at high latitudes was individually analyzed.The soil heat transfer parameters were changed,the ground temperature distribution was recalculated,and the average annual ground temperature was used as the evaluation index of thermal stability.The annual average ground temperature of the soil below the runway in the area will be above-1.5℃ after 20 years,and the frozen soil will degrade quickly.The relationship between the maximum displacement and the known soil resilience modulus was established,and the reaction modulus of the base top rebound was used as the static evaluation index.The frost heaving and thaw settlement deformations were calculated separately.The results show that the freeze-thaw deformation is larger than the static deformation.