Use of geosynthetics for stabilizing recycled ballast in railway track substructures

Traditional ballasted railway track substructure usually consists of graded layers of granular media of ballast and subballast (capping) placed above a compacted subgrade (formation soil). Ballast particles breakdown and deteriorate progressively under heavy train cyclic loading. Breakage of ballast is always associated with railway track deformation, which requires costly regular track maintenance in the form of replacing the degraded (recycled) ballast with fresh aggregates and subsequent re-compaction (tamping). In this paper, the use of geosynthetics for improving the deformation and degradation characteristics of recycled ballast is investigated. The prospective use of three different types of geosynthetics (i.e. geogrid, geotextile, and geocomposite) in enhancing the performance of recycled ballast under cyclic loading is examined using a large-scale prismoidal triaxial rig. A plane strain finite element analysis (PLAXIS) of the prismoidal triaxial rig is also carried out and used to obtain the optimum location of geosynthetics in railway track substructure. The results indicate that the use of geosynthetics for stabilizing the recycled ballast in railway tracks improves the performance characteristics of the track and consequently, reduces the track maintenance cost.