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

With the implementation of major national development strategies such as the Silk Road Economic Belt and the CMB economic corridor,China has planned and built a large number of highway projects in permafrost areas.However,due to the construction of asphalt highway in permafrost area,the water balance of the original permafrost under the subgrade is broken,and the strong heat absorption effect of the black pavement is caused by the upper limit of permafrost under the subgrade,and the subsidence deformation of subgrade pavement is serious.The traditional treatment of permafrost subgrade subsidence deformation mainly uses hot rod technology and replacement technology,but these methods have high cost,long construction period,waste pollution environment,large impact on traffic and so on.Polymer materials have the advantages of fast reaction speed,high tensile strength and good toughness,so polymer grouting technology is widely used in the treatment of hidden diseases of roads in the central and southeastern provinces of China,and good results have been obtained.However,the technology of polymer grouting repair has not been popularized in permafrost area,the main reason is that the polymer two-part material releases heat in the event of polymerization,and the law of heat on permafrost subgrade is not clear,and the study of interaction with permafrost subgrade under the coupling of traffic and temperature load has not yet been carried out.Based on the above background,taking the polymer grouting material and permafrost subgrade in permafrost area as the research object,the influence of the reaction exothermic of polymer grouting material on the temperature field of permafrost subgrade and the mechanical response law before and after polymer grouting to repair different disease degree emptying permafrost subgrade are studied.The aim is to provide theoretical basis and reference for the application of polymer grouting repair technology in the treatment of hidden diseases in permafrost area.The main research contents and achievements are as follows:1.The current research status of temperature field,thermodynamic coupling field,disease control measures and polymer materials of permafrost subgrade at home and abroad is summarized and analyzed,and the purpose and significance of this study are expounded.2.Based on the two-dimensional unsteady heat conduction theory,combined with the climatic characteristics of permafrost region,a numerical model of twodimensional heat conduction of polymer grouting material and permafrost subgrade is established by using Abaqus finite element software,and the influence law of material polymerization reaction exothermic on the temperature field of permafrost subgrade under different grouting conditions is analyzed.The results show that the material reaction exothermic will cause the temperature of the surrounding subgrade to increase,and the influence range increases with the increase of grouting quantity,but the overall influence range is small(20-30cm),and the influence can be mitigated by taking appropriate measures.3.Using Abaqus finite element software,a three-dimensional numerical model of permafrost subgrade is established,the mechanical response before and after grouting repair of emptying permafrost subgrade polymers under temperature-traffic load coupling is studied,and the influence law of different temperature conditions and different disease degree on pavement mechanical properties is analyzed.The effect of polymer grouting on the repair of different disease degree emptying disease was evaluated.The results show that there is a negative correlation between Mises stress and temperature in emptying permafrost subgrade under different temperature conditions,the vertical displacement is positively correlated with temperature,and the Mises stress and vertical displacement of the pavement are significantly reduced after the polymer grouting is repaired emptying permafrost subgrade,and the repair effect is different under different temperature conditions.4.The road model of permafrost subgrade in emptying is made,the effect of polymerization of polymer materials on the temperature field of permafrost Subgrade is studied,the bending and sinking of the pavement before and after the grouting repair of emptying permafrost is analyzed,and the rationality and correctness of the numerical simulation model are verified.