Dynamic Response Analysis Of CRTS Ⅱ Type Slab Ballastless Track On Subgrade During Earthquakes

Bridge and subgrade are the two basic forms which usually adopted in high speed railway. Our country is an earthquake prone country. When the earthquake occurred, the train may be running on the bridge and may also be driving on the subgrade. Researches of the ballastless track on bridge have more than on subgrade. Therefore, it has an important meaning to research dynamic response of ballastless track on subgrade under the earthquake.Firstly, the research situation of ballastless track, track and subgrade interaction and bridge and subgrade of ballastless track under the action of earthquake at home and abroad was reviewed. Secondly, the analysis method of structural seismic was introduced. At last, CRTS II slab ballastless track of subgrade was selected as object of study to research the dynamic response during earthquakes.The main research contents included are as follows. The ballastless track and subgrade interaction model under earthquake was establishmented by using ABAQUS finite element software. The characteristics of seismic wave and ballastless track structure were analysised. Spectrum method and time history were used to research the dynamic response of ballastless track under the earthquake. The effects of track and subgrade structure parameters to the ballastless track structure under earthquake were researched.The research results show that:(1)The most unfavorable earthquake wave incident angle alpha, beta is taken as 60 degree and 30 degree.(2)The results calculated by response spectrum method and the time history method have the same consistency for the same earthquake.(3)The CRTS II type slab ballastless track on subgrade belongs to the low frequency. Vibration mode is mostly transverse distortion.(4)Under the effects of earthquake, transverse effect of ballastless track structure is higher than the vertical effect.(5)Under the effects of earthquake, when the earthquake intensity increases 1 degree, stress and displacement will increase 1 times.(6)The dynamic response of ballastless track structure has not a uniform law under the different parameters of track and subgrade. In the seismic design of ballastless track and subgrade structure, appropriate structure parameters should be selected and the impact of various factors should be considered.