To main content

Cofra Vibro Compaction (CVC)

Compaction techniques form part of Cofra’s portfolio since 2005. Since that time we have compacted several tens of millions cubic meters with our compaction techniques. Our three compaction techniques are complementary to each other and are often used together on compaction projects. We use our Cofra Vibroflotation devices on reclamations where we need to compact a thickness larger than 7 to 9 meters. Our specialist are more than happy to tell you more about it

What it is

The Cofra Vibro Compaction (CVC) method, also referred to as Vibro flotation, is a technique used to densify loose granular materials at greater depths. A winged vibrator-section, with an eccentric weight, is located at the bottom of the vibroflot. A vibroflot consists of a vibrator and several followers to create a long needle that is penetrated into the soil. The vibrator generates horizontal vibrations that lead to a densified zone around the vibrator.

How it works

The compaction of the underground is initiated by high frequency vibrations, which lead to the rearrangement of the particles within the horizontal influence zone. These vibrations are generated at depth by the vibrator. It densifies a column of soil around the so-called flot.


The suitability of the method is more than other compaction techniques dependent on the grain size distribution and fines content. The material needs to be permeable enough to allow quick drainage of the added water during the compaction process. In practice this means less than 10% fines and less than 2% clay. During field trials at the start of a project, the horizontal influence zone is determined under different operational procedures and related to the project requirements. The outcome results in a center to center distance, also referred to as grid size.

Why it's used

Compaction is required to mitigate liquefaction risks or improve the bearing capacity and settlement behavior under loading of the underground. CVC compaction is often used on new reclamations to compact the subsoil up to requirements to avoid liquefaction under an earthquake.

The CVC results and required effort are related to the soil type, fines content and requirements. Applying Vibro- compaction will result in the following effects:

  • Soil densification due to vibration and particles re‐organization
  • Friction angle increase
  • Stiffness increase
  • Bearing capacity increase
  • Liquefaction mitigation
  • Limitation of settlement when applying load

Application area

Cofra Vibro Compaction is used in the following markets:

  • Infrastructure: The CVC technique is for example used for the compaction of embankments for roads, railways, runways and aprons for airports and port areas. The compaction can in this case be related to liquefaction mitigation but also to improve the load settlement characteristics of the substrata under dynamic loading (transport of heavy equipment or reduce the long term impact of impacts)
  • Dredging and land reclamation: CVC is often used to compact the deeper sections of reclamations up to specification
  • Mining: CVC can be used to compact thick spoil deposits before the rehabilitation of an area.
  • Construction: Cofra vibro compaction is used in the construction industry to mitigate liquefaction risks
  • Liquefaction mitigation: CVC is used for liquefaction mitigation in areas where loose saturated granular soil occurs below a depth of 7 to 9 meters.

 The following soil types are suitable for the use of CVC:

Website Diagram Cvc V2

How it is installed

The CVC method is executed by driving a large vibrating needle, called vibroflot, into the ground by means of water- and/or air-jetting. At depth the compaction phase starts and the vibroflot is either gradually, or in steps withdrawn, while vibrating heavily. The vibrations are generated by the winged vibrator-section, with an eccentric weight located at the bottom of the vibroflot. While compacting, granular material is added from the surface to fill the voids.

Csm Vibro Wide 58905Aa13d

Contact us (regional contacts on our contact page)

Business development Cofra

For new opportunities or partnering.

Estimation Department Cofra

If you require a quotation or need a budget for your project for any country in world outside our home markets.

Technical Sales Cofra

For design questions or technical information.

A selection of our compaction projects

Selected filters

CDC compaction for the Wasl Island development

Our Cofra Middle East crews compacted in 2022, 17,500m2 to create a new hotel resort on reclaimed land.


CDC compaction for Masdar Road

Our Cofra Middle East crews compacted in 2020, 32,000m2 to create a new road.

CDC compaction for Al Hudayriat Island

For main contractor NMDC, we are compacting the new artificial hills on the Island with a 16 ton Rapid impact hammer

CRC and CDC compaction for Dubai Waste center

A total of 182.000m2 was compacted in 2022 for the future Waste treatment center in Dubai

CDC compaction for Al Dhafra airbase

For an expansion on the Al Dafra airbase we have compacted in 2022, 700.000 m2 of area

CDC compaction for Jafourah Gas Plant

We provided two 16 ton CDC rigs between 2022 and 2023 for the site preparation of the Jafourah Gas plant in KSA