Study On The Application Of Thermal Insulation Technology In The Runway Subgrade Of Permafrost Regions

Thermal insulation technology is one of the main measures to deal with the problems of frost heave,thaw subsidence and permafrost degradation in permafrost areas.The heat transferred down from the top of the soil layer protects the thermal stability of the permafrost below.At present,this method has been successfully applied in highway and railway subgrade engineering in permafrost areas in my country,but the application research in airport grounds in permafrost areas in my country is still blank.Although some successful experience has been achieved in the application of thermal insulation technology to build permafrost airport runways abroad,the high latitude,high altitude and the difference in ambient temperature make the thickness change of permafrost in permafrost in our country,ground temperature dynamics,frozen soil Structure and other aspects are different from other countries.Therefore,whether thermal insulation technology can be effectively applied to the construction of airport runways in permafrost environment in my country is an important topic worthy of study.Based on the above background,this paper will use theoretical research,laboratory tests and finite element analysis methods,combined with the characteristics of permafrost in my country and different runway structural parameters,etc.In-depth research on the applicable conditions has been carried out to provide a reference for the construction of airports in permafrost areas in my country.The specific research contents and results of this paper are as follows:1.The basic physical and mechanical properties of XPS insulation boards with different thicknesses were measured,and the compressive strength,compressibility,thermal conductivity,water absorption,and the attenuation law of thermal insulation performance before and after compression deformation were obtained.2.The low temperature laboratory was used to simulate the permafrost foundation test with different thicknesses of thermal insulation boards buried under the annual temperature change,to monitor the temperature change law of the frozen soil foundation along the depth,and to analyze the thermal insulation effect of thermal insulation boards of different thicknesses.At the same time,the above indoor model test was simulated and analyzed based on the hydrothermal coupled temperature field model using Abaqus finite element software,and the simulation results were basically consistent with the temperature data collected by the test,which verifies the reliability of the finite element model.3.According to the climatic and geological conditions of the permafrost region in northern Heilongjiang,a permafrost runway subgrade model with thermal insulation boards is used to study the influence of different buried depths,thicknesses,runway widths,and completion dates of thermal insulation boards on the temperature field of the subgrade.4.According to the distribution characteristics of permafrost in my country,the high-latitude Mohe region and the high-altitude Nagqu region are selected,and according to the local climatic conditions,frozen soil quality,ground temperature and other conditions,combined with the influence of various structural parameters of the thermal insulation slab subgrade on the temperature field,the Mohe and Nagqu regions are discussed.The applicable conditions for the application of thermal insulation technology to the airport runway in Nagqu.