Reinforcement and mud-pumping benefits of geosynthetics in railway tracks: Model tests

Abstract

The railroad track is one of the few geosynthetic applications in which a geosynthetic is used for multiple functions, namely, reinforcement, separation, filtration and drainage. In the present study, static and cyclic tests were performed on full-panel railway track models laid on compacted soil subgrades. Tests were performed on model tracks with two different thicknesses of subballast layers and laid on two different subgrade soils, namely, Dhanaury clay and Delhi silt. Model tracks were adequately instrumented to record induced stresses and displacements in the track. Model tracks were reinforced with a geogrid or a geotextile or both at suitable interfaces. Track conditions after heavy rainfall were simulated. The model tracks reinforced with a geogrid at the ballast–subballast interface were more effective in reducing the tie displacements, ballast and subballast strains and subgrade displacements compared to the model tracks reinforced with a geotextile at the subballast–subgrade interface when Dhanaury clay was used as the subgrade soil. Conversely, the model tracks reinforced with a geotextile performed better with respect to reduced tie displacement, subgrade displacement and subballast strain compared to the model tracks reinforced with a geogrid when Delhi silt was used as the subgrade soil.