Study On The Interaction Mechanism Between Polymer Materials And Permafrost Subgrade Under Multi-field Coupling

Good transportation capacity is the primary foundation of a region's economic development.In recent years,my country has constructed a large number of highway projects in permafrost regions mainly in the western region.Because the permafrost area has been in a low-temperature climate environment for many years,the geological conditions are very special,resulting in frequent road diseases in the permafrost area,the severity of the disease is serious,the traditional highway maintenance technology has limited repair effects,and it is impossible to solve the root cause Various disease problems have brought great difficulties to road maintenance.At present,the application of non-destructive testing and polymer grouting integrated road disease treatment technology in non-permafrost regions has been very mature,but due to the obvious thermal effect of the grouting material used,it has not been applied in permafrost regions.Therefore,the development of low exothermic polymer grouting materials and the study of their exothermic properties are of great significance for the maintenance of highways in permafrost regions.In this paper,based on the above background,the thermal analysis test method is used to systematically study the heat release mechanism,curing heat release and thermal conductivity of low heat release polymer grouting materials,and compare with ordinary polymer grouting materials.The low heat effect of the new low exothermic polymer grouting material was demonstrated,and through the finite element numerical analysis,the influence range of the solidified heat release process on the temperature field of frozen soil subgrade was analyzed.The main research results are as follows:(1)Based on the chemical reaction principle of polymer materials,the heat release mechanism of the material solidification was studied,and the influencing factors of the heat release rate of the polymer materials were analyzed through Fourier's law of heat conduction and heat transfer theory.(2)Through laboratory tests,the temperature of the center and surface of the material during the curing process of low exotherm and ordinary high polymer materials was tested with time at an ambient temperature of-10?? 30?.The density of the material and the ambient temperature were studied.The influence of the curing exothermic process is analyzed to obtain the relationship between density and the highest reaction temperature and the rate of initial rise and fall.The curing and exothermic process of polymer materials mainly undergoes three periods: heating,constant temperature and cooling.In the initial stage of heating and cooling,the temperature of the center and surface of the material changes linearly with time,and both increase with the increase of density.(3)Under the same test conditions,the thermal property parameters(specific heat capacity and thermal conductivity)of the low exotherm and ordinary polymer materials and the heat of curing were tested through thermal analysis tests and thermodynamic calculation methods.The thermal conductivity and heat storage of the material were studied and analyzed ability.(4)Based on the research on the heat release and heat conduction properties of the two polymer materials,by comparing and comprehensively analyzing the thermal effect of the material as a whole,the results show that: compared with ordinary polymer materials,low heat release materials have lower heat release efficiency and adiabatic insulation The ability is stronger,the impact on the low temperature environment is smaller,and the scope of application is wider.(5)Based on the law of unsteady heat conduction and the basic theory of subgrade temperature field,the two-dimensional heat transfer model of low exothermic polymer grouting material and frozen soil subgrade was established using Ansys finite element analysis software.The influence range of slurry material solidification and heat release on frozen soil roadbed.