The CDC (Cofra Dynamic Compaction) method, is a fast and
reliable technique for the compaction of sand and gravel. The
underlying strata are densified from the existing surface by
dropping a 9 to 16 ton pounder from a specified height at in-
tervals ranging from 40 to 80 blows per minute. Depend-
ing on the soil type, requirements and effort, a densifica-
tion can be measured up to 8 meters below the surface.
The project
The CDC compaction was executed on the project “Khalifa port”
located inbetween Abu Dhabi and Dubai in the United Arabic Emi-
rates. The material in the reclamation area comprised of sandy
to gra velly material. For the project, a total area of 2,300,000m2
required compaction with the CDC method. Cofra was awarded
the contract to use the CDC method to achie ve the required
compaction at depth. The work was executed between October
2008 and June 2010.
Equipment
The equipment used during the project consisted of two RH40
and one CAT385C base units with a 16 ton CDC hammer of the
second genera tion. Depending on the soil conditions, a 1.5, 2
me ter and 2.6 meter diameter foot was used for the compac-
tion.
Compaction lay-out
Compaction was executed mostly in one phase depending on
the soil conditions. Center to center distances between 2.0 and
3.5m were used depending on the required depth of influence
and initial compaction levels.
Review
The execution of the project showed that the technique is per-
fectly suitable for the compaction of significant granular bodies.
Valuable data was gathered during the execution of the project
to improve/develop the technique. The machines proved their
competiveness and production expectations.
CofraC
dynamic compactionProject ReportProject
Khalifa Port
Required Technique
Dynamic Compaction
Year
2008-2010
T +31 (0)20 693 45 96, F +31 (0)20 694 14 57, www.cofra.com, [email protected] Cofra BV
P.O. Box 20694 1001 NR Amsterdam, The Netherlands