Soil improvement by internally reinforced stone columns

Abstract

Granular columns have been used as an effective technique for improving the engineering behaviour of soft clays and loose sand deposits. This paper presents the results of an experimental investigation on sand columns internally reinforced with horizontal wire meshes made of plastic, steel and aluminium materials. Loading tests were performed on prototype reinforced sand columns in a stress-controlled chamber that contained normally consolidated clay. The objective of this investigation was to establish the load-carrying capacity of these columns in light of the presence and intensity of the reinforcement. The performance of the reinforced sand mass was examined, by direct shear testing, in terms of angle of shearing resistance, strains to peak strength, bearing ratio, and brittleness of the system post-peak. A theoretical model is proposed to predict the load-carrying capacity of these columns. The values predicted by the proposed theory compared well with the results of the present experimental investigation as well as those available in the literature. A design procedure is presented for practitioners.