Effectiveness of Geosynthetics at Preventing Subgrade Instability under Cyclic Loading

American Society of Civil Engineers (ASCE)
Publication Type:
Conference Proceeding
Geotechnical Special Publication, 2023, 2023-March, (GSP 341), pp. 427-437
Issue Date:
Full metadata record
Recent laboratory investigations indicate that low-to-medium plasticity subgrade is vulnerable to subgrade fluidisation due to excessive local hydraulic gradients that develop under cyclic loading. This study primarily investigates the role of geosynthetics to dissipate accumulated excess pore water pressure (EPWP), and minimise particle migration and subgrade fluidisation in typical railway track environments using the dynamic filtration apparatus (DFA). The experiments indicate there is an upward migration of moisture and fine particles towards the ballast-subgrade interface which cause the soil specimen to soften (slurry) under undrained cyclic tests. The combined prefabricated vertical drains (PVDs) and geocomposite system can dissipate the rapid accumulation of EPWPs due to the reduction in drainage path lengths and additional confinement at the ballast and subgrade interface. The excess pore pressure gradients (EPPG) that developed at different depths of the soil specimens were measured to assess the potential for the upward migration of fine particles.
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