Ordinary and Encased Stone Columns with Two Different Relative Densities


Stone columns technique is most commonly used in increasing bearing capacity,reduces and controls the compressibility and accelerates the rate of consolidation of softsaturated clay. During the last four decades, the technique has been utilized worldwideand proved successful results. Several modifications have been proposed to increase theefficiency of this technique such as addition of additives, use of special patterns ofreinforcements, encasing the stone columns with geonet or geogrid to provide extraconfinement that enhances the bearing capacity and reduces the settlement drasticallywithout compromising its effect as a drain.The present paper focuses on the behavior of soft saturated clay reinforced withordinary and geogrid encased stone columns. The investigation was performed bothexperimentally through small scale models and through numerical techniques. Theinfluence of relative density of the back fill material and the presence of the encasementare the main parameters investigated.Ordinary stone columns revealed an increase of 20% in the carrying capacity whenthe relative density of the backfill stone aggregates increased from 23% to 71%,furthermore the efficiency of the encasement was more pronounced at lower relativedensity.