Non-linear soil behaviour on high speed rail lines

K. Dong, D. P. Connolly, O. Laghrouche, P. K. Woodward, P. Alves Costa

Research output: Contribution to journalArticle

9 Citations (Scopus)
9 Downloads (Pure)

Abstract

This paper gives new insights into non-linear subgrade behaviour on high speed railway track dynamics. First, a novel semi-analytical model is developed which allows for soil stiffness and damping to dynamically change as a function of strain. The model uses analytical expressions for the railroad track, coupled to a thin-layer element formulation for the ground. Material non-linearity is accounted for using a ‘linear equivalent’ approach which iteratively updates the soil material properties. It is validated using published datasets and in-situ field data. Four case studies are used to investigate non-linear behaviour, each with contrasting subgrade characteristics. Considering an 18 tonne axle load, the critical velocity is significantly lower than the linear case, and rail deflections are up to 30% higher. Furthermore, at speeds close-to, but below the non-linear critical velocity, dynamic amplification is highly sensitive to small increases in train speed. These findings are dependent upon soil material properties, and are important for railway track-earthwork designers because often 70% of the linear critical velocity is used as a design limit. This work shows that designs close to this limit may be still at risk of high dynamic effects, particularly if line speed is increased in the future.
Original languageEnglish
Pages (from-to)302-318
Number of pages17
JournalComputers and Geotechnics
Volume112
Early online date9 May 2019
DOIs
Publication statusPublished - Aug 2019

Keywords

  • High speed rail track design
  • Rail-track dynamic amplification
  • Railroad track stiffness
  • Railway critical velocity
  • Soil-subgrade non-linearity
  • Thin-layer element method (TLM)

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Computer Science Applications

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