Vibro Replacement (VR)

Vibro Replacement is a product of the Vibroflotation process and is used to increase bearing capacity, decrease settlement, and mitigate liquefaction potential for all types of planned structures including buildings, embankments, dams, tanks and towers.

This technique is used in soils that do not respond well to vibration alone e.g. stiff soils like clay, soils with more than 15% silt.
Ground improvement is achieved by creating columns of either crushed stone or concrete, of which the latter can be reinforced.
The process enables increased load bearing, reduces settlement and even improves the shear resistance of the ground being treated.
Technically proven worldwide and very cost effective.

There are two primary construction methods of Vibro Replacement.
a. Wet Top Feed
b. Dry Bottom Feed


Wet Top Feed

 

 

 

 

This is the most commonly used and most cost-efficient of the deep vibratory replacement methods.
Stone is fed directly from the surface with the aid of a wheeled loader or similar into the void that has been created by the Vibroflot.

Phase 1: Penetration

Assisted by air and/or water jetting at the nose cone, the Vibroflot penetrates to the required depth under its own weight. Once the Vibroflot has reached the design depth, the air and/or water at the nose cone is reduced or switched off.

Phase 2: Replacement

Crushed stone backfill is fed from the ground surface into the created void. The horizontal forces of the Vibroflot, laterally compacts the stone against the surrounding soil.
This process is repeated up to the designed cut-off level, forming a well compacted, tightly-interlocked stone column surrounded by compacted soil of enhanced density.


Dry Bottom Feed

 

 

 

 

Dry Bottom Feed refers to the process of placing the stone using a skip or other medium into the receiving hopper which is located at the uppermost part of the Vibroflot assembly. From there the stone is fed down through a series of stone feed pipes, which are mounted onto the side of the Vibroflot / follower tubes and ejected beneath the specially adapted nose cone into the base of the column.
With this system, no water is used for penetration.
It offers a cleaner and more reliable solution in comparison  with the simpler wet top feed method.
Hence, it is preferred where the environment plays a critical role in project execution.

Phase 1: Penetration

When suspended from a standard crawler crane, the Vibroflot penetrates to the required depth under its own weight.
When mounted on a leader of a suitable base machine the Vibroflot penetrates to the designed depth with the assistance of a pull down / crowd winch, thus increasing the efficiency and speeding up the
penetration time. When as an attachment to an excavator the Vibroflot penetrates to the required depth with the assistance of the boom.

Phase 2: Replacement

Crushed stone is introduced (with the aid of a skip or other medium) into the hopper and is fed down the stone supply tubes to the specially adapted nose cone. The Vibroflot is then lifted a set value and the stone is discharged to the underside of the nose cone. The Vibroflot slightly re-penetrates to a set value and the horizontal forces of the Vibroflot laterally compacts the stone against the surrounding soil.
This process is repeated up to the designed cut-off level, forming a well compacted tightly interlocked stone column surrounded by compacted soil of enhanced density.

Vibro Compaction (VC)

X Ref Vibroflot Specs Vibro Configurator