Review of Size and Loading Conditions for Large-Scale Triaxial Testing

摘要

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.