Review of size and loading conditions for large-scale triaxial testing

Timothy D. Stark, Stephen T. Wilk, Robert H. Swan

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The large particle size of railroad ballast and the wide range of loading conditions make it difficult to appropriately represent ballast behavior in laboratory shear testing. This paper presents an overview of the advantages and disadvantages of large-scale triaxial compression testing of ballast, how it can be used to represent field ballast conditions, and typical results. Minimum size restrictions and diameter along with appropriate confining stress, loading frequencies, and deviator stresses are discussed with examples of the range of loading conditions experienced in the field from field monitoring and numerical modeling. In triaxial compression testing, a specimen diameter of six times the maximum particle size is required. In addition, standard confining stresses can range from 0 kPa to 72 kPa, and the deviator stresses can range from 50 kPa to 360 kPa.

Original languageEnglish (US)
Title of host publicationRailroad Ballast Testing and Properties
EditorsRichard Szecsy, Timothy D. Stark, Robert H. Swan
PublisherASTM International
Number of pages11
ISBN (Electronic)9780803176553
StatePublished - 2018
EventInternational Symposium on Railroad Ballast Testing and Properties 2018 - New Orleans, United States
Duration: Jan 24 2018Jan 24 2018

Publication series

NameASTM Special Technical Publication
VolumeSTP 1605
ISSN (Print)0066-0558


OtherInternational Symposium on Railroad Ballast Testing and Properties 2018
Country/TerritoryUnited States
CityNew Orleans


  • Ballast
  • Confining stress
  • Normal stress
  • Triaxial tests

ASJC Scopus subject areas

  • General Materials Science


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