Frost Heaving And Vibration Response Monitoring Of Heavy Haul Railway Subgrade In Seasonal Frozen Region

In order to ensure the safe operation of heavy haul railway in seasonal frozen area,the problem of subgrade frost heaving needs to be solved.The action of freeze-thaw cycle and the vibration of heavy haul train are the fundamental causes of the railway subgrade diseases in seasonal frozen area.The research on frost heaving and dynamic response of subgrade under freeze-thaw condition can provide objective basis for subgrade design,disease prevention and disaster assessment of railway in cold regions in China.Firstly,according to the selected section of typical heavy haul railway disease in seasonal frozen region,according to the relevant theory of frozen soil,the disease and influencing factors of Railway Subgrade in seasonal frozen soil area are introduced,and the monitoring scheme is developed to carry out on-site monitoring;Secondly,the temperature,water content and frost heaving deformation of subgrade are monitored and analyzed,and the mechanism of frost heaving is analyzed;Finally,through the analysis of the dynamic characteristics of subgrade stability under train load,some suggestions are put forward to prevent seasonal Railway Subgrade Frost damage.This paper mainly carried out the following research work:(1)Taking the Ningwu section of Shuohuang Railway as the engineering site,the typical section of frost heaving is selected as the monitoring section,the monitoring scheme and the sensors were arranged,and the remote monitoring system was constructed,which can realize long-term static collection and dynamic collection,and obtain detailed monitoring data.On-site penetration test and indoor physical property test were carried out to master the physical characteristics of subgrade filling in the test section.(2)The static monitoring data in freeze-thaw period are sorted out,and the development degree and production law of Frost Heaving in freezing period are analyzed,including the changes of ground temperature and water content before and after freezing,as well as the changes between frost heaving deformation and freezing depth,ground temperature and water content,etc.(3)This paper focuses on the dynamic responses law of subgrade caused by heavy train.The attenuation laws of subgrade vibration acceleration were analyzed,the characteristic value of subgrade vibration acceleration before and after freezing,the variation characteristics of vibration response speed and dynamic displacement are summarized.