ABSTRACT
Researchers and practicing engineers have long recognised that the ballast bed accumulates plastic deformation under cyclic loading. Despite this, little or no effort has been made to develop realistic constitutive stress-strain relationships, particularly modelling plastic deformation and particle degradation of ballast under cyclic loading. Several researchers attempted to model the constitutive behaviour of soils and granular aggregates under monotonic loading (e.g. Roscoe et al., [1]; Schofield and Wroth, [2]; Lade, [3]; Pender, [4]), and various approaches were made to simulate the cyclic response of granular media. Some are quite innovative and successful to a limited extent. Nevertheless, constitutive modelling of geomaterials under cyclic loading still remains a challenging task.
