Effect of stabilised granular column on the pressure settlement behaviour of clay

The paper presents an assessment of the suitability of an alternate material for use as stone aggregates in stone column. A series of load tests were conducted in the model test tank using single granular column (30 mm in diameter and H/D ratio of 6) installed in a clay bed prepared at a water content of 30% to evaluate the improvement in pressure-settlement behaviour. The clay is reinforced with the different types of granular columns such as sand column, slate column, stone column, slate-sand column, stabilized granular column composed of slate, fly ash, cement and stabilized granular column made up of slate, fly ash, lime, gypsum. All the stabilized granular columns reinforced in clay bed have shown a significant improvement in pressure-settlement behaviour and ultimate bearing capacity. The increase in ultimate bearing capacity was highest for clay reinforced with stabilized granular column composed of slate, fly ash and cement followed by stabilized granular column made up of slate, fly ash, lime and gypsum. The increase in ultimate bearing pressure of about 200% and 93.29% was observed for clay reinforced with a column made up of slate waste-fly ash-cement and slate waste-fly ash-lime-gypsum respectively over the bearing pressure of clay reinforced with stone column. For clay reinforced with stabilized granular columns a significant increase in ultimate bearing pressure was noticed as the reinforced clay bed was room cured for 1, 7 and 28 days respectively. The obtained results for unreinforced clay and clay reinforced with stone column compares favourably with the literature.