Some aspects of the shear behaviour of unreinforced and geosynthetic-reinforced rail ballast

This paper presents the experimental results related to the shear behaviour of unreinforced and geosynthetic-reinforced rail ballast. Large-scale direct shear tests were performed using fresh Latite ballast and geogrids with different aperture sizes. The laboratory experimental results indicate that the shear behavior of both unreinforced and geosynthetic-reinforced ballast follow a non-linear trend at low confining stress. The results further suggest that the shear strength of ballast can be improved significantly when reinforced with geosynthetics. However, the shear strength at the ballast-geosynthetic interface is found to be a function of the geogrid aperture to particle size ratio. It is expected that this study will assist in selecting suitable geosynthetics for successfully stabilising a given ballast gradation, to reduce track maintenance costs. Keywords: Rail ballast, Interface behaviour, Direct shear test, Geosynthetics