Subgrade Fluidization Under Cyclic Loading and Preventive Measure by Geosynthetics

The demand for increased axle loads and speeds of trains can diminish the stability of track substructure, leading to potential particle migration or slurry pumping under critical drainage conditions. This paper primarily focuses on the role of geosynthetics in mitigating the risk of soil fluidization potential under cyclic load. Laboratory experiments were conducted to evaluate the effectiveness of geosynthetics including geotextiles, geocomposites, and prefabricated vertical drains (PVDs). The laboratory study indicates that subgrade instability primarily occurs due to the migration of fines towards the subgrade surface and the substantial increase in moisture content (MC). Dynamic Filtration Tests (DFTs) reveal that geocomposite inclusion in rail tracks can reduce the fluidization potential of soft soils and the combined prefabricated vertical drains-geocomposite system can be used to mitigate the critical excess pore water pressure (EPWP) that accumulates in shallow or deeper soil layer due to activated radial drainage paths.