Utilization of steel waste as granular stone materials in stone columns along with geotextile in the direction of sustainable development

The filling material of the columns is generally sand, gravel or crushed stone which are sometimes called stone columns or gravel columns. The implementation of this system is widely used in geotechnical engineering to increase bearing capacity, reduce settlement and accelerate integration. The use of industrial wastes such as steel slag in soil stabilization can be an environmentally friendly, sustainable and cost-effective technique for solid waste disposal. There are many studies which have been conducted on the bearing capacity and settlement of improved soils with stone columns with or without geosynthetic. However, a very limited number of studies on conventional stone columns and steel slag columns with or without confinement and geosynthetic under lateral loading have been investigated. In this paper, the lateral load capacity of steel slag granular column-sand environments has been investigated using a large-scale direct shear test device. The effects of column material type (steel slag and sand), column diameter and the type of geosynthetic on the shear strength parameters of column-sand composites have been investigated. The experimental results show the effectiveness of using steel slag columns to improve the lateral load performance of sand. The results indicate that the maximum stress increases by 20 to 70% and the internal friction angle increases by 200 to 800% compared to the sand without slag column with increasing the diameter of the column from 5 to 25 cm, respectively.