Predicting the Behavior of a Synthetic Energy Absorbing Layer for Subballast Using Nor-Sand Model

The granular layers of a conventional railway substructure, such as ballast and subballast or capping layer, are prone to particle breakage, and are comparatively more expensive than recycled waste materials in terms of capital and maintenance costs. Utilizing waste materials like mining waste such as steel furnace slag-coal wash (SFS + CW) mixtures and energy absorbing materials such as rubber crumbs (RC) for transportation infrastructure presents notable economic advantages, while being environmentally sustainable. Accordingly, prior investigations have examined the appropriateness of combining RC and SFS + CW as a viable alternative to conventional railway substructure materials, particularly in relation to the subballast layer. This paper presents the prediction of the behavior of steel furnace slag, coal wash, and rubber crumb (SFS + CW + RC) mixtures with a RC content of 20%, using the Nor-Sand model. The theoretical model is validated using static drained triaxial test data reported by Qi et al. (J Mater Civ Eng 30:018276, 2018).