Mapping relationship between uneven settlement of subgrade and rail deformation in subgrade-bridge transition section and its dynamic application

Abstract

The uneven settlement of subgrade-bridge transition section has a great influence on the driving safety and comfort of high-speed vehicles. This paper studies the mapping relationship between uneven settlement of subgrade and rail deformation in this section and it has been used to analyze the dynamic characteristics of the high-speed train when it is passing through the transition section. After the mechanism analysis of rail deformation, the subgrade-bridge transition section with CRTS-III slab ballastless track is built by finite element method (FEM). Mapping relationship between uneven settlement of subgrade and rail deformation can be obtained by large amounts of calculation. Based on the rail deformation curves from FEM model, the functional expression of the mapping relationship is given using least squares polynomial method. Finally, based on train-track coupled dynamics, the dynamic behaviors of the high speed train are analyzed on different conditions. The results show that there is a mapping relationship between settlement of subgrade and rail deformation, which can be given by a function. The function can describe the rail deformation accurately and reliably in transition section. The uneven settlement amplitude will not influence the wheel and rail force. However, the acceleration of carbody will increase with greater amplitude of settlement. The results of this paper can be the reference to the construction and maintenance of subgrade-bridge transition section.