Simulation of railway infrastructure with asphalt layer for tracks in Sweden

With the introduction of high-speed trains over the past few years, as well as withan increase in traffic loads and volumes, the attractiveness and competitiveness ofthe railway transport system have increased. This leads to the need to develop newcost-effective ways in railway construction, providing an increase in the life cycle ofthe railway track and reducing the need for maintenance.In several European countries, Japan, and the USA, asphalt mixtures, also called“bituminous mixtures”, are used as such an alternative solution in both traditionalballasted and ballastless railway designs. International experience has shown thatbituminous mixtures have good technical characteristics and can meet many of therequirements of modern railway construction, especially when it comes to the useof asphalt materials in ballasted tracks. However, there is a lack of knowledge andexperience in using bituminous mixtures in railway construction in the northernregions and harsh winter conditions.In this thesis, the development of two- and three-dimensional models of ballastedrailway track with an asphalt sub-ballast layer is presented. The analysis of thestatic and dynamic characteristics of the whole model and the asphalt layer exposedto different temperatures is carried out using the finite element method (FEM) inthe COMSOL software. Simulation for all conditions is carried out with a trainspeed of 200 km/h. The relationship between various temperatures from 30 °Cto +30 °C and the stress-strain behaviour of the asphalt sub-ballast layer is alsodetermined. The results of the study show that both under the influence of lowand high temperatures, the stresses and strains in the asphalt layer are quite small.Besides, the use of asphalt sub-ballast in the track structure reduces deformationsand stresses acting on the subgrade surface