Vehicle System Dynamics Vol. 45, No. 6, June 2007, 565–581 Finite element calculations of rail vibration countermeasures HÅKAN LANE*, SEBASTIAN BERG and MARTIN LARSSON Department ofApplied Mechanics, Chalmers University of Technology, Sven Hultins Gata, S-412 96 Gothenburg, Sweden Elastic waves may constitute a nuisance for people living close to high-speed lines. In order to decrease the spread of vibrations, it is common to reinforce the ground with lime cement columns. This article presents the results of simulations of three different ways to install the columns. The calculations have been done with an integrated rigid body – finite element model. Equations from various physical domains are merged into one big system. The results indicate that the straight configuration works best to protect the track. When attention is focused on preventing vibrations from the soil, the leaning column method is more effective. The chosen technique would depend on the aims of the countermeasure. Keywords: Elastic wave propagation; Railway systems; Computational dynamics AMS Subject Classification: 74H45; 74L10 1. Introduction High-speed train traffic in Sweden dates back to the early 1990s. Different from many other countries, no new dedicated lines were installed. The self-steering bogie of the new X2000 train enabled it to run on conventional lines. The drawback of this strategy became evident shortly after traffic had commenced on the West coast between Malmö and Gothenburg. A number of complaints of excessive vibrations were reported, especially close to the small town of Ledsgård. The situation with a track running close to a river leads to a very flexible subground with low wave propagation velocities. As a consequence of the high level of vibrations, trains had to pass through the most sensitive region at a speed considerably lower than the normal operating velocity. An extensive test and measurement program was carried out [1]. Several different ways of mitigating the problem were discussed. Finally, the choice fell on the insertion of lime cement (LC) columns. The soil is bored or grouted to make space for a mixture of lime and concrete, which reacts with the clay and solidifies to pillars. The replacement of soft clay with material with a higher Young’s modulus leads to a structure with higher wave propagation speeds and less susceptibility to dynamic stress waves. In Ledsgård, the columns were inserted right underneath the track. While the advantage of this approach is its proximity to the source of the vibrations through the wheel–rail–sleeper interaction, the need to remove the track during installation led to a *Corresponding author. Email: hakan.lane@sm.chalmers.se Vehicle System Dynamics ISSN 0042-3114 print/ISSN 1744-5159 online © 2007 Taylor & Francis http://www.tandf.co.uk/journals DOI: 10.1080/00423110601076363