Study On The Dynamic Response Characteristics Of High Filled Embankment By Train In Seasonally Frozen Region

China is a big country of frozen soil in the world,and its permafrost area is widely distributed,among which the distribution area of seasonal frozen soil accounts for approximately 53.5% of the country’s land area.In addition,with the rapid and efficient development of our country’s economy,the national railway industry has entered a period of rapid development.With the continuous increase in train freight.and the continuous increase in the speed of passenger transport,research on the embankment in the seasonally frozen region has commenced.However,the study of the dynamic response of trains in the seasonally frozen region is not sufficient.The problem of highfilled embankment in the frozen area needs to be solved urgently.This paper relies on the high-filled embankment in Fengning section of Zhangtang heavy railway,and compiles the VDLOAD subroutine based on FORTRAN language,which carries on the secondary development to ABAQUS,and realizes the movement of the threecarriage trains.In addition,the finite element model of high-filled embankment under the action of train loads in seasonally frozen ground was established using the artificial boundary of infinite element.The spatial and temporal distribution of high embankment temperature field and the dynamic response and influencing factors of embankment with high embankment in seasonally frozen area were analyzed.The result were compared with field data to verify the reliability of the results.The research results have theoretical and practical value for the design and construction of similar high-fill embankment in the seasonally frozen ground and the prevention of disease in the later period.The main research contents and achievements are as follows:(1)The temporal and spatial distribution of temperature field for high-filled embankment in seasonally frozen ground was studied based on the field temperature data.In the distribution of high-filled embankment temperature field,the distribution of the internal temperature time history curve is approximately cosinusoidal.With the depth increasing,the temperature amplitude decreases,and the temperature vertical transmission has hysteresis.(2)The dynamic stress amplitude of the surface layer of the high-fill embankment under different freeze-thaw conditions is different.The freezing period is the maximum,and the melting period is the smallest,and the normal period is somewhere in between.The driving train will cause the vertical dynamic stress,horizontal dynamic stress and vertical dynamic stress in the embankment.(3)The vertical dynamic stress in the high-filled embankment during the freezing period,melting period and normal period is nonlinear under the influence of internal damping,and it is approximately a power-exponent function distribution,and the value is attenuated with increasing depth.The decay rate is from fast to slow.About 80% of the vertical dynamic stress of the surface bed is lost in the range of 0~3 m.(4)The dynamic stress of the high fill embankment is affected by the axle load and speed of the train and the freezing and thawing state of the embankment.The influence of the axle load on the dynamic stress is obviously greater than that of the speed.