Vibro Stone Column


 

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.


This technology is well suited for the improvement of firm and soft soils (silts, sandy silts, loams and non-homogeneous soils) as well as non-cohesive soils where enhanced properties are needed. Stone Columns are typically installed under the structures such as factories, warehouses, residential buildings, container terminals, road and rail embankments, etc.

Typical load that can be carried by a single stone column ranges from 200 to 300 kN. The columns are arranged in a square or triangular grid with a spacing ranging from 1.5 m to 3.0 m so that the soil replacement factor is within the range from 15% to 35%.

Stone Column can be used for:

  • Railway and Roadway Embankments  
  • Retaining Walls
  • Storage Tanks
  • Commercial Buildings
  • Industrial Warehouses 
  • Residential Buildings
  • Container Terminals
  • Liquefaction Mitigation

Comprehensive improvement: able to increase the shear strength and stiffness of the improved soils and accelerate consolidation in soft cohesive soil due to the columns drainage property.

Liquefaction mitigation: well-adapted to the mitigation of liquefaction potential.

No spoil: in the course of the column formation, the surface soil structure is undamaged and there is no excavated material. Hence, no need for removal of earth mass.






SEE THE PICTURES