Stabilisation of granular media and formation soil using geosynthetics with special reference to railway engineering

Railway ballast breaks down and deteriorates progressively under train cyclic loading, and soft formation soil fails due to repetitive stress, leading to costly rail track maintenance. Using geosynthetics, track conditions can be improved and maintenance costs can be reduced. This paper addresses the potential use of geosynthetics for improving the deformation characteristics of rail ballast and formation soil. The prospective use of different types of geosynthetics was investigated using a large-scale prismoidal triaxial rig, and a plane strain finite element analysis (PLAXIS) of the rig was carried out to obtain the optimum location of geosynthetics in rail track substructure. A large-scale consolidometer was also employed to determine the effect of prefabricated vertical drains (PVDs) in optimising the accelerated primary consolidation of track soft formation. This paper also includes a section where recommendations are made on how to prepare the stability of rail tracks on surface formation soils considerably disturbed/remoulded by the Asian tsunami in Sri Lanka. The research findings reveal that geosynthetics have a good potential for resilient track construction and for reducing the cost of track maintenance.