Importance of non-linear soil behaviour on modelling rail track response

Abstract

This paper presents the simulation of linear rail track response using a threedimensional finite element model considering the non-linear soil subgrade behaviour. The innovation of this work upon the available literature is that besides linear and emphasis on equivalent linear analyses, a non-linear analysis is used as reference to take into account the shear strain dependence of the stiffness and damping in soils. The three-dimensional finite element methodology is similar to that used by other authors and has been validated in previous work with experimental results of the authors and other numerical models from the literature. A layer-by-layer update of stiffness and damping is used in the equivalent linear model. The non-linear behaviour is based on the Iwan parallel model. The study shows that for the presented case the equivalent linear model improves upon the linear model in predicting the non-linear soil response. The track response is also studied and it is shown that the linear equivalent approach presents an appreciative approximation to the non-linear behaviour while being simpler to implement and requiring less computational resource