Vibro replacement improves and densifies granular soils by installing aggregate columns using a depth vibrator.

Common Uses

  • Improve bearing capacity
  • Reduce settlement
  • Reduce liquefaction potential

Technical Details

Vibro replacement was developed by our parent company, Keller, in Europe. It can be performed by the wet top-feed process or the dry bottom-feed process.

During the wet top-feed process, a crane or specially built rig suspends the downhole vibrator, allowing the vibrator to use its weight and vibrations to penetrate the soil to the target depth. Water jets at the tip of the vibrator can assist with the penetration rate. The aggregate, crushed stone or recycled concrete, is added at ground surface to annular space created by the advancement of the vibrator. The added aggregate fills the void at the vibrator tip as the vibrator is raised several feet. Then the vibrator is lowered again to densify and displace the underlying aggregate. This process is repeated in lifts until the point where a dense, aggregate column is constructed all the way to the ground surface.

The dry bottom-feed process follows the same process as described above, with two exceptions. In this process, there are no water jets and an attached feed pipe is used to feed the aggregate to the tip of the vibrator. Sometimes pre-drilling is needed at the proposed treatment location to allow the vibrator to reach the target depth through any dense strata. Both methods reinforce and densify the treatment zone soils using a high modulus aggregate column.