Three-dimensional numerical analyses of pervious concrete column for soft soil improvement

Stone column (SC) or granular column is widely used as a soil improvement method for flexible foundations such as oil storage tanks, embankments and rigid foun­dations. The confining pressure exerted by the surrounding soil allows the SC to develop its bearing capacity. The soft soil surrounding a SC may not provide sufficient lateral confinement. So, the design bearing carrying capacity may not be achieved. In such soils, a pervious concrete column (PCC) may be applied which deals with reinforcement as well as drainage. PCC can be constructed up to the full depth of soft soil or on the upper portion of a stone column up to which bulging is predominant. This study presents a parametric analysis of the performance of SCs, PCCs and composite columns (CCs) using three-dimensional numerical analyses. The parameters consider are: PCC diameter, PCC length in CCs surrounding soft clay cohesion, and full PCC length. Furthermore, the load transfer mechanism of pervious concrete is compared to that of a SC. In comparison to ordinary SCs, the findings of this study show that pervious concrete columns have a substantially better load carrying capacity and experience less lateral displacement. Furthermore, in a CC, the length of pervious concrete up to four times the column diameter may be sufficient to enhance the load carrying capacity of an ordinary SC.