High Speed Railway Adapted To Large Deformation After Subgrade Construction Research On Long Pillow Ballastless Track

Subgrade settlement is the main disease of subgrade section and bridge and tunnel transition section,and is also one of the most prominent problems in the bridge and tunnel connection section of ballastless track construction.At present,there are two solutions for subgrade settlement: fastening adjustment and subgrade control.The former has limited adjustment ability,while the latter has problems of high cost,long cycle and low precision.The research team proposed a new type of long pillow height adjustable ballastless track,the main feature of which is that the sleeper is supported on the side and the supporting surface is conical.The side support plate is used to isolate the side of the sleeper and the side of the track bed bearing groove,which is convenient to adjust the height of the track structure in a large range by replacing the side support plate or long sleeper.The main research contents and conclusions of this paper are as follows:(1)For the new long pillow height adjustable ballastless track,the finite element model and the dynamic model of interaction between the vehicle system and the new long pillow height adjustable ballastless track,the bottom support height adjustable ballastless track and the CRTS type I double block ballastless track are established.(2)By comparing the dynamic response with the field measured results and taking a number of dynamic responses as evaluation indexes,the correctness of the new long pillow height adjustable ballastless track dynamic model is demonstrated.(3)By comparing three side support plates with different elastic modulus,it is found that the selection of side support plates with larger elastic modulus has less influence on the dynamic response of vehicle system.(4)Through the comparative study of the dynamic response of the vehicle and the track after adjusting the height,the adjustment ability of the new long pillow height adjustable ballastless track is proved.Compared with the adjustable bottom support height,it is found that the dynamic index of the new long pillow height adjustable ballastless track is smaller than that of the bottom support height adjustable ballastless track after lifting,indicating that the whole model has advantages in maintaining the stability of the track structure.The new long pillow height adjustable ballastless track adopts the replacement of side support plate to realize the track elevation,which effectively avoids the problems of large investment,long period and low precision existing in the settlement of roadbed.In addition,the overall structural stability of the ballastless track under this scheme will gradually improve during the operation of the line,and the indexes of vehicle smoothness and safety also meet the required limits.It has a good application prospect in railway construction.When the train speed is less than 250km/h,the solution can solve the problem of subgrade settlement below 137 mm.