Experimental Studies on Groups of Stone Columns with Various Shapes of Geotextile

A wide range of treatments has been proposed to improve soft soils. However, increasing construction costs combined with today’s environmental considerations will undoubtedly make the stone column technique a good alternative to the other techniques. In this paper, results obtained from stone columns installed in clay soil are presented and discussed. To do this and because in real conditions stone columns are used in groups, a series of experimental tests were performed on the groups of 3 and 12 stone columns and compared with the single stone columns. The stone columns were reinforced with a vertical encasement, horizontal layers, and a combination of both. It is found that, in a group of stone columns, the use of the combination of vertical encasement and horizontal layers outperformed other shapes. In addition, both group arrangements of stone columns result in more increase in bearing capacity in comparison with the single stone columns. However, the group of 3 stone columns had better efficiency despite its lower replacement area ratio.