Stone Columns are made with various methods with the use of different equipment units depending on the depth and diameter of the columns and parameters of the soil to be improved. The popularity of this method resulted in its widespread use.
The typical Stone Columns (SC) are formed by inserting an electrical or hydraulic vibroflot mounted on a base machine. Depending on the depth of the columns, the following units are used: an excavator (up to 7 m), a purpose-built rig (up to 20 m) or a crawler crane (up to 40 m).
The installation starts by inserting the vibroflot into the ground up to the design depth and the process is often assisted by injecting compressed air, water or air-water mix. Subsequently, aggregate backfill is placed into the space formed and compacted in stages by adding the aggregate at every 0.5 m. Depending on the methods, aggregate is supplied via a feeding pipe connected to the vibroflot (bottom feed) or from the level of the working platform along the vibroflot (top feed). Typically the columns formed are 50 to 120 cm in diameter depending on the subsoil stiffness.