Research On Dynamic Characteristics And Parameters Of Ballastless Track-Subgrade Structure

Ballastless track is widely applied in the building of high speed railway and passenger dedicated line with its advantages of high stability, high ride comfort and few maintenance. As the basis for the ballastless track, soil subgrade, especially the bedding, holds up the loading generated when the train runs at high speed. The ballastless track-subgrade dynamical response generated by the vibration loading of train is a complex dynamic process, involved three factors which are vehicles, track and subgrade. Therefore, we must research dynamic characteristics of the bedding, determine the discipline of dynamic stress, deformation and acceleration in the bedding. In this way, we can guide rational design of ballastless track-subgrade structure.This paper is based on the ground of the experiment line of sui-yu railway. The author adopts theoretical analysis, integrating field investigation and numerical simulation, studying on the dynamical response of ballastless track-subgrade structure. The main research work and conclusion as follows:(1)This paper comprehensively summarizes the status and problems of vehicles-track-subgrade structure's dynamical response, overviews the ballastless track structure styles and their characteristic, discourses the subgrade stiffness which matchs ballastless track-subgrade structure,(2)It simulates the high moving train load by three function through analyzing the mechanism producing by train. It overviews soil's dynamic stress-strain features and elastoplastic constitutive relation.(3)It briefly introduces the large-scale test model of ballastless track subgrade and the comprehensive field test.(4)It establishes 3D numerical model of slab ballastless track-subgrade structure by software FLAC-3D, and does dynamic simulation by using the numerical model. It analyzes the influence feature of subgrade structural lay's stiffness and thickness to the dynamical response of slab ballastless track-subgrade structure; it also analyzes the influence feature of the different train axle and speed. (5)Through comparing the calculation results with measured results, the numerical model and calculation parameters are proved to be reasonable. Therefore, we can grasp the dynamical characteristic of ballastless track-subgrade structure.