Dynamic compaction is performed by dropping large weights between 10 and 30 tons on loose soil. Cranes are used to drop large steel or concrete grids from a height of up to 100 feet.
When the grid makes contact with the loose soil, it transfers the compactive energy into the soil. This displaces much of the air space between the particles, resulting in a more solid, stable soil mass.
Dynamic compaction is a faster and more economical method of mitigating problems associated with loose soils. It has gained popularity as a preferable method to densify soils over conventional methods, such as replacement of loose soils, or the addition of heavier soils.