Granular columns have been used widely over the years to improve the load-bearing capacity of soft soils. Conventional granular columns are composed of stone aggregates, a non-renewable natural resource. Meanwhile, the global stockpile of plastic waste poses another serious threat to the sustainable existence of lives on our planet. This paper highlights the results of laboratory model tests performed on an embankment supported over a soft clay bed improved with granular columns (GC) and plastic granular columns (PGC). The model embankment was subjected to static and cyclic loading tests. The cyclic loading was applied in a 4-stage varying amplitude and single-stage loading. The experimental results show that the vertical load-bearing capacity of the soil bed improved by the granular column is increased by 71-135 % under static loading, respectively. The stresses induced in the column and soil bed were measured using earth and pore pressure transducers. Using GC and PGC, the cyclic load-induced settlements were reduced for both floating and end-bearing conditions compared to unreinforced soil. Using geosynthetic encasement further enhances the loading-bearing capacity, stress concentration ratio, and excess pore water pressure dissipation of the soil bed. The excess pore water pressure in unreinforced clay beds is reduced significantly. The stress concentration ratio (n) of the encased column improved bed is 1.51 and 1.50 times that of the non-encased end-bearing and floating columns. Geosynthetic encasement of GC and PGC significantly contributes to cyclic load-bearing capacity. The application of GC and PGC in soft clay improvement for the development of transportation routes and railway embankments is wellsuited based on the findings of this study.