Laboratory Study on Single Stone Columns Reinforced with Steel Bars and Discs

Abstract

Stone columns are widely used as an effective and environmental friendly improvement method for increasing the load-carrying capacity of soft clay soils. In very soft clay soils, reinforced stone columns are used because of the lack of the lateral confinement created by the surrounding soil. To provide lateral additional confinement, geosynthetics are usually used. This study intends to evaluate the use of vertical steel bars and horizontal steel discs as an alternative way to geosynthetics to investigate the effect of reinforcement on the footing load-carrying characteristics. Therefore, some large-scale laboratory tests were conducted on stone columns with diameters of 80 and 100 mm and a length to diameter of 5. The results show that changing the arrangement of the bars to a higher stiffness leads to increase in load-carrying capacity. Reinforcing the full-length of the stone columns with the bars in comparison to half-length reinforced has significant influence in capacity. However, in the case of horizontal discs, this increase is negligible. Also by decreasing the space of the discs, load-carrying capacity increases. Moreover, the performance of the vertical reinforced stone column seemed to be better than the horizontal reinforced stone column. The increase of load-carrying capacity in reinforced stone columns with vertical bars or horizontal discs is higher than geotextile reinforcement in the same conditions.