Rolling Dynamic Compaction (RDC)

Rolling Dynamic Compaction (RDC)

CON-FORM's RDC in ActionRolling Dynamic Compaction (RDC) is an efficient, effective and environmentally friendly way of compacting and consolidating in situ, weak and marginal material at depth. Tackling in-depth problems in this way re-engineers the ground and improves its shear strength and weight bearing capacity, thereby reducing the need for more costly solutions.

The depth of influence depends upon the type and moisture content of the soil but can be in excess of 5 metres. RDC is an invaluable process for brownfield and other development sites where a geotechnical issue exists in the sub soil.

The RDC process will identifies pockets of soft compressible material, voids and other unacceptable conditions in the sub grades which can then be treated.

RDC is carried out until effective refusal of the material being treated is achieved. RDC provides rapid, effective coverage of a site and on general earthworks projects can allow thicker fill layers to be placed. Where large thicknesses of granular fill are required on sites it can be placed in 1m - 1.5m layers.

CON-FORM has different sized modules, the most effective of which can be calculated to impart approximately TWICE the impact energy of any other high impact rolling system available in Europe.

Applications for Rolling Dynamic Compaction (RDC)

Close up of CON-FORM's Rolling Dynamic CompactionRDC on its own can not change poor soils into good, but is an extremely powerful tool when used in conjunction with CON-FORM's soil stabilisation and modification capabilities.

RDC can be used to break up pavements, hardstanding areas, concrete slabs, etc. as well as helping separate re-bar from its integral concrete structure.

The recovered aggregates can then be incorporated into the ground solution thereby reducing the need for imported materials.

RDC used in the development of brownfield sites and when dealing with made ground, has a key role as it can minimise the impact of future differential settlement.

Table Comparing CON-FORM's RDC with Traditional Methods
  Traditional RDC CON-FORM's RDC
Specification Pentagonal Triangular Square 8 Ton Square 12 Ton
Energy Rating (kJ per blow) 15 25 50 100
Sides on Masses 2 x 5 sides 2 x 3 sides 1 x 4 sides 1 x 4 sides
Width per Mass (mm)  900 900 1300 1300
Operating Width
Double Pass (m) 3.6 3.6 2.6 2.6
Single Pass (m) 1.8 + gap 1.8 + gap 1.3 1.3
Effective Zone Width
Double Pass (m) 4.0 4.0 4.6 4.6
Single Pass (m) 1.8 + gap 1.8 + gap 2.3 2.3
Operating Mass Towed 12.5 13.5 14 18
Operating Speed (km/h)  9 9 12 12
Mobile Speed (km/h) 25 35 50 50
Nominal Depths
Fill (m) 0.7 1.5 1.0 1.5
In-situ (m) 1.5 2.5 2.5 3.5
Dynamic Mass (Ton) 2 @ 5.25 2 @ 5.5 1 @ 7.8 1 @ 12
Lift Height (mm) 150 230 150 150
Blows (per min) 90 - 130 80 - 110 120 120
Nominal Static Linear Load (kg/cm) 58 / 52 61 60 90

Advantages of CON-FORM's Rolling Dynamic Compaction

  • Highly efficient way of compacting and consolidating soil to its optimum level.
  • An effective mechanism for compacting and consolidating at depth, weak marginal soils in-situ without the need for piling or vibro-piling.
  • Environmentally friendly in its execution.
  • Produces a controlled uniform solution across 100% of the treated site.
  • Tackling problems at depth enables CON-FORM to re-engineer the soil and improve its shear strength and weight bearing capacity, thereby reducing the need for more costly solutions.
  • The process exposes pockets of soft material, voids and other unacceptable conditions immediately.

Typical RDC site settlement analysis showing differential settlement acheived across a siteCON-FORM has the most effective RDC unit in the UK.

Other units only apply around 50kN/m2 of force.

CON-FORM's units can apply 100kN/m2, giving approximately TWICE the impact energy of any other.

This means that CON-FORM's RDC treatment has an increased productivity rate leading to an overall reduction in contract time.