Analysis On The Dynamic Characteristics Of CRTS Ⅱ Type Slab Ballastless Track On Subgrade And The Parametric Study

CRTSⅡ type slab ballastless track is a new type of ballastless track structure which is introduced, digested, absorbed and re-innovation by our country in recent years. Because this track structure have the short time applications in the construction of Chinese high-speed railway, there are many issues need to be studied, such as:the dynamic characteristics analysis and evaluation of CRTS Ⅱ type slab ballastless track; the influence of fastener stiffness, mortar elastic modulus, the supporting layer of elastic modulus and the foundation bed parameters to the track system and how these parameters are selected, and so on.This paper summarizes the overview of the development of domestic and foreign ballastless track and overview of the development of track dynamics, and briefly introduce the structure and characteristics of CRTS Ⅱ type Slab and ballastless track on subgrade. Study on the use of large-scale finite element software ABAQUS to establish the main issues involved in the dynamics of the finite element model in order to determine a more rational approach should be used. According to the vehicle-track-subgrade interaction principle and finite element theory, use of large-scale finite element software ABAQUS established the dynamics finite element model of CRTS Ⅱ type slab ballastless track on subgrade, analysis and evaluation the dynamic performance of CRTS Ⅱ type slab ballastless track on subgrade. These analyzes include:vehicle safety and comfort, dynamic response analysis of the track structure and subgrade. In addition, this paper also studied the influence of fastener stiffness, mortar elastic modulus, the supporting layer of elastic modulus, the foundation bed parameters and other important parameters to the ballastless track system.By analyzing the research shows that:when the vehicles to200km/h-350km/h speed through CRTS Ⅱ type slab ballastless track on subgrade, the safety and comfort of vehicle can meet the requirements, part of the dynamic response values of CRTS Ⅱ type slab ballastless track on subgrade are relatively small, fully able to meet the requirements of ballastless track system dynamic response aspects, the ride comfort of ballastless track is better; should use low stiffness of the fastener to meet the dynamic displacement of the track geometry and track requirements; in order to reduce the rail acceleration, the acceleration of the orbital plate, the horizontal stress in the track plate, mortar compressive stress, supporting layer compressive stress, a higher modulus of elasticity of the mortar should be used; supporting layer elastic modulus increase or decrease is advantages and disadvantages in terms of CRTS Ⅱ type slab ballastless track on subgrade, should be comprehensive considered; an appropriate increase in the base bed surface and the bed bottom of the elastic modulus can effectively reduce the dynamic response of subgrade. This paper through analysis on the dynamic characteristics of CRTS II type slab ballastless track on subgrade and the parametric study, summed up the law, provide a reference for further optimizing and improving CRTSⅡ type slab ballastless track on subgrade.