Study On The Coupling Vibration Of High-speed Raiway Ballastless Track-subgrade System

With the development of the high-speed railway, the train has been speeding constantly. The issue concerning the dynamic stress of the track-subgrade system on which the loading of the rapid train acts has become a major subject encountered in railway construction in our country. The thesis conducts detained analyses and numerical simulation calculation for the vibration response of the ballastless-subgrade system of the high-speed railway and under the action of the loading of the train. Main work and findings of the study is as follows:(1) By consulting many relevant references at home and abroad, the thesis reviews the history and the present study of the models of the train, the track and the subgrade as well as other models and points out the problems existing in previous studies; in addition, the thesis analyzes the dynamic evaluation criteria for the train-ballastless-subgrade system.(2) After the establishment of a vertical coupling vibration model of the train-ballastless-subgrade system by finite element method, the coupling between the train and the track is realized at the element level by the use of moving-connecting element, by which the dynamic establishment of the model of the system is greatly simplified.(3) With the vertical coupling vibration model of the train-allastless track-subgrade system, and with matlab used as the second development platform, the thesis composes the program for calculating the vertical vibr ation response of the system simulation calculation, along with which nu merical simulation calculation is also conducted. According to the calcu lation, the maximum value of vertical vibration acceleration of the train is1.632m/s2, which indicates relatively good moving stability within the saf ety limit; and the displacement of rail in the model is greatly influenced by the structural parameters of the under-rail foundation on and the devia tion of the maximum peak value can reach40%.(4) With the use of Ansys finite element software, a three-dimensional model is established for analyzing the dynamic response of the ballastless track-subgrade system, and the numerical simulation calculation of the dynamic response of the ballastless track-subgrade system is also conducted. In addition, the thesis discusses respectively the influence of the speed of the train, the unevenness of the track, the structure of the subgrade and two-way traffic on the dynamic response of the ballastless track-subgrade model. According to the calculation, the influence of the uneven track on dynamic stress is more striking, and so it is necessary to control strictly the amplitude of the unevenness of the track of high-speed railway.