| The development of the road is of great significance to the improvement of the overall level of the national economy,so it is vital to ensure the long-term stability of the road.The subgrade is the foundation of the whole road,the quality and service life of the road depend on the quality of the subgrade.The northeast of China is in a typical seasonal frozen area.The roads in this area had various frostbite problems frequency,for example,road slurry,surface network cracks,uneven road surface settlement and so on.By analyzing the mechanism of frostbite,we found that the freezing and thawing cycle is serious for the strength of the easily frozen soil which is typical of the powder clay.This typical subgrade is more likely to be destabilized by the combination of freezing and long-term vehicle loads,and the various problems of the road are created in result.According to the previous research,the improved soil has excellent insulation properties,to use this typical soil as the subgrade can reduce the damage of the freezing and melting cycle as the subgrade.In addition,the improved soil has excellent mechanical stability because of its inner composition.So putting forward the design that can we use the improved soil subgrade,and it can reduce the effect of the long-term effect of traffic load on the road of season freeze by improving soil and manage the problems of road disease and maintain the long-term stability of the road in this paper.(1)In laboratory experiments,the basic model of the clay road was set up to simulate the soil road and the comparison group.By applying dynamic load,the variation of dynamic stress of modified soil and powdery clay was studied with the depth changes.Considering the load peak and load frequency,the dynamic response rule of the soil was studied,and the dynamic stress and acceleration time curve of the two soils were analyzed.(2)Build the laboratory model through ABAQUS finite element software,and then the results are compared with the data from the laboratory.In addition the displacement of the soil under the dynamic load is obtained and finally the accuracy of the model is verified.(3)Studying on the specimen in the process of freezing and thawing cycle improvement soil under the condition of full load and overload 20% load of dynamic stress and the acceleration index change situation after the five freeze-thaw cycle.(4)In the experiment,considering the load peak and the loading frequency,the dynamic stress and acceleration curve of the modified soil are measured after five permafrost cycles.After the experiment,we analyze the change trend of dynamic stress and acceleration of silty clay and improved soil after five times freeze-thaw cycle,which are based on the different factor,and we analyze the stability of modified soil after freezing and thawing under dynamic load in a more comprehensive way.Based on laboratory test and finite element simulation of the obtained before the improved soil freezing g and thawing,we find that the analysis of improved soil as road subgrade filling satisfy normal performance.Then after five times freezing and thawing cycle to two kinds of soil respectively,the results show that the improved's dynamic stress of soil and the stability of acceleration are better than the silty clay,and the dynamic characteristics of the improved soil is better than that of the silty clay.Finally,the change of the peak load and load frequency,two kinds of soil was studied under different factor influence,after five times freeze-thaw cycle dynamic stress,the acceleration of change trend,the results show that under the effect of different factors,the improvement of soil under moving load after freeze-thaw stability is much better than that of silty clay,from last season frozen area roads long resistance to deformation and maintain the stability of the point of view,improved soil was more suitable for use as subgrade filling. |
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