What is the standard for soil compaction? - HENGDA RIC

Typical compaction requirements for a project may range from 90% to 95% of standard Proctor for non-structural areas to 98% or more of modified Proctor for heavily loaded pavements.

This compaction energy brings the soil particles into a more densely packed structure. The compaction energy is transmitted safely and efficiently as the compaction foot remains in contact with the ground. No flying debris occurs during the compaction process. The hammering of the foot by the impact weight is the reason of the sub-soil compaction. Indeed, the huge amount of energy developed upon the hammering process and transmitted to the ground through the foot, pushes the backfilling material into a denser structure.

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.

In the urban environment, the RIC technique has a number of specific advantages compared to the conventional drop weight dynamic compaction (DC) technique. These can be summarised as follows:

• The dedicated plant used is relatively small, with moderate mobilisation and operating costs compared with conventional drop weight dynamic compaction. Thus, smaller sites may be economically treated. Rigging and de-rigging times are also quite rapid.

• Treatment can be carried out in closer proximity to existing structures and services vulnerable to vibration damage. There is generally no danger from flying debris.

• Discrete, relatively small foundation areas can be treated without compromising production.

• Energy is more efficiently transferred through the compaction foot which remains in contact with the ground. It is important to recognise that those specifying RIC ground treatment understand the nature of the particular treatment process employed and its potential benefits for the ground conditions being considered. 

With RIC the total energy input will have a major influence on the depth of compaction. With the rapid impact compactor the energy per blow is very much smaller than conventional DC and the fixed energy per blow of typically 8.4 t.m is not the major influence on the depth of compaction due to the progressive top down improvement of the treated ground. Of much greater significance to the effective depth of compaction is the number of blows at a compaction point or the energy applied overall to the ground surface. For typical impact spacing, 35 blows will impart about 170 tonne.m/m2 of energy. This level of energy input has produced significant compaction to depths between 3 and 4 m in non-engineered generally granular fill and up to about 3 m in natural sand and silty soils using a 7 t hammer.