Stabilisation of ballast and subgrade with geosynthetic grids and drains for rail infrastructure

Rail tracks are often placed on ballast that is intended to provide a free draining and sound load bearing platform to ensure track stability and maintain proper alignment. In recent years, the increased demand of heavier and faster trains has posed greater challenges to the railway industry for improving efficiency and track stability while reducing maintenance costs. High traffic induced stresses always result in large plastic deformations and degradation of ballast, which in turn, leads to significant loss of track stability. The deformation and degradation of ballast are influenced by factors such as the amplitude and number of load cycles, gradation of aggregates, track confining pressure and the angularity and fracture strength of individual particles. Geosynthetic materials can also play an important role in improving the efficiency and performance of a ballasted rail track. This paper highlights laboratory testing and field trials carried out to demonstrate the beneficial use of geosynthetic grids and drains for rail infrastructure. The use of numerical models for analysing and predicting track behaviour is also elucidated.