Experimental Study on Effect of Varying L/D Ratios of Steel Slag Columns on Bearing Capacity of Soft Clay

Abstract

Rapid urbanisation and growth of infrastructure in the present days resulted in dramatic increase in demand for land space. Presence of soft clay deposits in construction sites poses major problems to the structure resting on it during or after construction. A different approach for stabilization has been obtained by incorporation of steel slag columns, which is a by-product of steel manufacturing industry. Straight shafted granulated steel slag column group was adopted for which the ultimate load carrying capacity was derived from the lateral resistance offered by the surrounding soil. Floating type steel slag columns resting on soft clay layer was arranged in equilateral triangular pattern. This pattern of arrangement was preferred as it was known to provide a more uniform consolidation between columns as per IS 15284 (part 1).Well graded granulated steel slag of size range 2mm-10mm with specific gravity 3.57 and moisture content 2.76% was used. It also had an abrasion value, impact value and crushing strength of 5.47%, 27.75 % and 39.38% respectively. A comparison was made between unreinforced and reinforced soil and variations in bearing capacity and settlement was determined for different L/D ratios. L/D ratios of 3, 5, 6, 8, 10 for steel slag columns has been adopted .Settlement reduction factors for reinforced clay bed was found to be 1.75, 1.85, 2.53, 4.1, 6.1 times of unreinforced clay soil for the L/D ratios of 3, 5, 6, 8, 10 respectively. The bearing capacity factor Nc was obtained as 5.51, 9.09, 12.670, 15.71, 20.26, 24.83 for different L/D ratios of 3, 5, 6, 8, 10.