Stone Columns Constructions
Stone columns are constructed by experienced contractors using specialist equipment. The construction uses an excavator with a vibrating probe to feed stone into the ground, forming a vertical column of stone.
Some stone column rigs feed stone into the ground through the vibrating probe, exiting at the bottom, and other rigs require the stone to be fed in from the ground surface down the vertical hole in the ground. Both types use a vibrating probe that densifies the surrounding soils to help feed the stone into the ground.
Construction Sequence:
- Construction of a gravel plug at the bottom of the cylindrical steel casing.
- Bottom driving on the plug using an internal ram (piston) causes the casing to be driven into the soil and displace the surrounding soil laterally.
- When the required depth is reached, the expulsion of the plug with the cylindrical internal piston.
- Realization of the compacted stone column, formed by adding and expelling the required amount of gravel.
How do stone columns improve the ground?
Stone columns help to limit the amount and consequences of future liquefaction by:
- Densifying the soil through vibration and introducing stone into the soil
- Reinforcing the soil creating a stiff composite soil mass.