ABSTRACT
Until today, the vast majority of railway design engineers have regarded ballast as an elastic granular medium. Although the accumulation of plastic deformation under cyclic traffic loading is evident, most researchers are primarily interested in modelling the dynamic resilient modulus of ballast. Limited research has been conducted on the constitutive modelling of ballast under cyclic loading, while some researchers have attempted to simulate the plastic deformation empirically. Despite spending a considerable annual sum for the construction and maintenance of railway tracks, the design is still predominantly empirical in nature (Suiker, [1]). A large number of researchers have modelled the elasto-plastic deformation of sand and other granular media under monotonic and cyclic loadings. As ballast is comprised of coarse aggregates, these elasto-plastic deformation models are useful and may serve as a framework for developing a specific model to simulate ballast behaviour including plastic deformation and particle breakage under cyclic loading.
