Vibro compaction is a ground improvement technique that densifies clean, cohesionless granular soils with a downhole vibrator. It’s a technique first developed by Keller in the 1930s that we’ve used on thousands of projects since.
Process
The Keller-made vibrators were first developed in the 1930s to compact granular, cohesionless soils at large depths from the ground surface, without any excavation. The Keller-made vibrators are far advanced today and, through research and development, we continue to develop vibrators that can compact soils efficiently with wide grids and large depths close to 50m.
A vibrator hung from a crane is lowered into the ground with penetration usually helped by water jetting. The energy from the vibration reduces the inter-granular forces between the soil particles, making them denser as the vibrator is raised in lifts. Sand backfill is then poured in from ground level to compensate for any decrease in soil volumes. More backfill is added and compacted and the vibrator is gradually removed until it has built up to ground level.
Vibro rigs can be fully instrumented with an on-board data acquisition system. Data from the system, such as amperage and lift rate, can then be recorded and displayed in real-time on an in-cab monitor. The production data can also be monitored from any Keller office by installing a mobile sim in the data recorder.
Common uses
- Reduce foundation settlement
- Increase bearing capacity, allowing reduction in footing size
- Increasing stiffness
- Increasing shear strength
- Reduce permeability
- Mitigate liquefaction potential under a seismic event
- Prevent earthquake-induced lateral spreading
- Increase slope stability
- Permit construction infills
- Very effective for compacting reclaimed lands
Advantages
- A versatile ground-improvement method that can be adjusted to a wide variety of soil conditions and foundation requirements
- Offers an economical solution for ground improvement
- Can be carried out to almost any depth
- Relatively quick execution so subsequent structural works can follow very quickly
- Environmentally-friendly as uses natural and in situ materials
- Negligible noise levels during production
- Maintains original site elevation where backfill is used
Quality assurance
The vibro equipment we use is designed and manufactured by our in-house equipment manufacturer exclusively for use by Keller companies.
In-house quality production manager software enables us to capture and analyse data in real time and validate the performance of the ground improvement being carried out.
A variety of production parameters are generally logged during execution including depth, current, pull down force, uplift/pull down sequence, time and date and element number.
Field trials can also be used to verify column production parameters, along with static load tests, single or group, column material compressive strength tests, and column diameter verification.
Related techniques
Related resources
Related projects
Residential
Zuhha Island
Keller successfully performed ground improvement works using the Vibro Compaction technique and improved the in-situ soil up to a depth of 18m below the working platform level.
Residential
Oasis Lagoon - Phase 3
The Oasis Lagoon project is a unique project. An old lagoon, with a huge quantity of water inside, needed to be backfilled with ground improvement.
Commercial and leisure
Dubai Harbour
Vibro compaction of 7 million m³ of sand across an area 380,000 m² of land.
Energy and utilities
Al Zour Refinery
An optimized and smart design with a wider grid resulted in considerable cost savings for our client.
Energy and utilities
Upper Zakum Islands
A total of 27 million m³ of calcareous sands were compacted, that is about 11 times as big as the Great Pyramid of Giza!
