Study On Characteristics Of Railway Subgrade Diseases And Remediation Technologies In High-altitude And Cold Regions

China is the world’s third-largest country with permafrost,and permafrost is widely distributed throughout both the seasonal frozen regions in the northwest and northeast.Due to the cyclic freezing and thawing,railway embankments are often affected by frost damage.In addition to causing direct deformation of the embankment surface,frost damage also weakens the soil strength,resulting in frequent irregular changes in the geometric dimensions of the railway line,unstable line quality,and a serious threat to the safety of train operations.Therefore,controlling the stable deformation of the embankment and addressing embankment disease problems is a critical scientific issue that needs to be solved urgently.This thesis takes the severely diseased section of the Jingbao Railway under the jurisdiction of the Hohhot Railway Bureau as the research object,and through the deployment of monitoring points on-site,studies the distribution law of the temperature field of the seasonal frozen soil embankment and the frost damage treatment technology of the embankment in high-altitude cold regions.The main research results are as follows:(1)By studying the environmental characteristics of the seasonal frozen soil area of the Jingbao Railway in Inner Mongolia,the characteristics of embankment disease in the high-altitude section of the Jingbao Railway were analyzed,and the characteristics and variation laws of permafrost embankment damage were obtained.(2)Combined with the treatment project of the frost damage section in the high-altitude section of the Jingbao Railway,the K490+200K490+415 section of the Jingbao high-speed railway and the K905+112K905+226 section of the Jingbao Railway freight line,which are located in the concentrated area of high-altitude frost damage,were selected as monitoring sections.The frost damage embankment in the high-altitude section of the Jingbao Railway was comprehensively tracked and monitored,and the frost heave mechanism and causes of embankment frost damage in this section were identified,providing a scientific basis for the treatment of frost damage embankments in the high-altitude section of the Jingbao Railway.(3)Based on the basic theory of embankment temperature field in permafrost regions,a finite element embankment temperature field calculation model was established using ABAQUS software and numerical simulation method.The distribution and variation laws of the frost damage embankment temperature field in the high-altitude section of the Jingbao Railway after freezing and thawing cycles were analyzed in depth,and the impact mechanism of temperature change on embankment frost damage was explored,providing reliable basis for the treatment of embankment diseases in the high-altitude section of the Jingbao Railway.(4)Starting from the frost heave prevention and control methods in the high-altitude section of the railway embankment,data research was conducted to analyze the mechanisms and effects of measures such as cutting off water sources,drainage,replacement,grouting reinforcement,and extrusion on frost heave prevention and control in the high-altitude section of the railway embankment.These measures were implemented in the frost heave prevention and control of the Jingbao Railway embankment in the high-altitude area,which improved the physical and mechanical properties of the soil in the railway embankment,reduced the water content,and reduced frost heave,thus achieving the effect of reinforcing the embankment and ensuring the safe and stable operation of the railway.