Nature and type of soil, i.e. sand or clay, grading, plasticity.
Water content at the time of compaction.
Site conditions, e.g. weather, type of site, layer thickness.
Compactive effort: type of plant (weight, vibration, number of passes)
The RIC system uses "controlled impact compaction" of the ground using a 9-ton hammer dropped from height between 0.3 m to 1.2 m onto a 1.5 m diameter steel patent foot delivering about 26,487 to 105,948 Joules of energy per drop. RIC can be used to densify loose soils down to a depth of about 4 m to 6m. RIC consists of an excavatormounted hydraulic pile-driving hammer striking a circular plate (patent foot) that rests on the ground. The tamper typically strikes the plate at a rate of 40 to 60 blows per minute.
RIC can be used to improve bearing capacity and reduce liquefaction potential of loose soils. The compaction sequence is designed to work from the outside in, so that compaction of the lower zone soils occurs first followed by compaction of the upper zone. Data monitoring during the compaction process and the online display in the operator’s cab enables compaction control, an economic application of the compaction tool, and a work integrated quality control. The total impact depth of the impact foot, the number of blows, and the final settlement of the impact foot after a blow define the stopping criteria.
The rapid impact compactor as a means of quickly repairing damage runways. It works by imparting dynamic energy through a falling 'drop-weight, which is dropped from a controlled height onto a patented foot.
With heights of 9 to 12 tones applied to the foot , the 'drop-weights' falls from relatively short height of only 1.2 meters at a rate of 40 to 60 times a minute.
Effective compaction depths vary with the nature of hte soil compacted, but depth of up to 8m have been reached with a 9t rig.
This results in The Rapid Impact Compactor transferring energy to the ground in a significantly more effective manner as the 'foot' stays in contact with the surface, never actually leaving the ground. It is because of this impacting sequence that we can ensure that the transfer of energy into the ground is carried out in the most efficient way possible.
The selection of the compaction method (DC or RIC) and plant type for a particular project, will depend on ground and groundwater conditions, and requirements for design and execution. Each system has merits and limitations. It is important that these are understood and considered in the design and application of DC/RIC on a particular site and in the context of the prevailing ground conditions. Indeed, it may be necessary for more than one technique to be employed at a particular site to gain maximum benefit.