Loose soil or uncompacted fill is compacted at depth by penetration of a vibrating probe combined with a large input of water to cause localized soil liquefaction. This settles grains in a denser matrix and increases overall compaction of soil mass.

A crane inserts a vibrating probe into the existing soil, injecting air and or water. The probe is then raised and lowered by tiers from its base to the working platform level, to form a column of dense sand.

Applicable in clean granular soil, this process reduces the risk of liquefaction and densifies soil down to depths exceeding 30 m. The technique can also increase bearing capacity and reduce settling.