Dynamic compactation (for ground improvement)
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The technique consists of methodically and repeatedly dropping heavy steel weights onto the surface of soils requiring improvement. The resulting impacts create powerful compression and shear stresses that reach considerable depths and induce volume reduction within the soil masses, improving their geotechnical properties. Using specially modified powerful crawler cranes, the weights or tampers are hoisted and released as a quasi free fall. The weight of these tampers usually varies between 10 and 18 tonnes, but with special hoisting systems it can reach 30 tonnes or more to achieve greater improvement depths. The tampers are typically dropped from 10 to 25 metres above the work platform.

The energy applied to the ground upon impact is measured in tonne-metres (t-m) and the magnitude of the energy per drop is a determinant factor in the degree and maximum depth of improvement achieved. Other significant parameters affecting both the depth and degree of improvement are the overall design of the energy application program, the proper phasing of the work, the right number of impacts per grid point, and the close monitoring of the soil response as work progresses. The increase and the subsequent rate of dissipation of pore pressures, the variations of induced settlements throughout the site, heaving, etc. are all elements which must be closely monitored and evaluated throughout the treatment.

Dynamic Compaction is an extremely rapid technique compared to other methods, and in loose granular soils of 12 metres or less, it is unquestionably the most economical of all existing soil improvement techniques.