Study On The Defoemation And Structure Adaptability Of Subgrade

As the passenger special lines start up, such as Beijing—Shanghai high-speed railway,Wuhan—Guangzhou high-speed railway,Zhengzhou—Xi'an high-speed railway and so on. The construction of high-speed ballastless track comes to a new period. In order to study further on the mechanical response and behavior and the design method, the Ministry of Railways of China decided to build a test section of the ballastless track. The full length of SuiYu main line is 12.65km, which is the first test section in China—Sui(Suining)Yu(Chongqing) test section.The internal stress of sub rail foundation of high-speed ballastless track is very complex. Mainly appears in two aspects: one is the instability of strength fatigue of subgrade; the other is instability of deformation fatigue of sub rail foundation. So the control of deformation of subgade becomes the core problem when analysis the high-speed ballastless track. But in the exiting research, the control of subgrade mainly on strength, and lack of enough recognition.This paper is supported by the scientific planning project of ministry of railway, the number is 2005K004-(G), and the name be the key technologyinvestigated by experimental in Suiyu ballastless track test section——the studyof sub structure. In this paper, the nonlinear finite element software ABAQUS was used, which developed by the company of HKS in America. And builded the three-dimensional finite element model, used the exiting train load model, mainly analyzed the influence of acceleration,vertical dynamic displacement,dynamic stress and related deformation mechanical responses by different speed of the train load and design parameters. The deformation and structure adaptability of subgrade was discussed preliminarily. The calculation result indicate that the value of vertical dynamic stress increase led to the surface layer of subgrade stiffness; the value of vertical acceleration and vertical dynamic displacement decrease led to he surface layer of subgrade stiffness; the base stiffness has a critical stiffness was 80MPa, when the stiffness was more than 80MPa, the range of variation of dynamic stress and vertical dynamic displacement decrease, at the same time vertical acceleration is on rapid descending trend. And each mechanical response show disciplinary fluctuate as the speed increase. At the same time, a prediction model for cumulative permanent deformation has been used, and analyzed the permanent deformation of subgrade and differential settlement, the result indicate that the permanent can satisfy well of the design.