Dynamic compaction

The process involves dropping a heavy weight repeatedly on the ground at regularly spaced points, usually laid out in a systematic fashion such as a grid.

The weight and the height from which it is dropped determine the force delivered to the ground surface and thus the amount of compaction that occurs.

Depending on the degree of compaction desired, the weight may vary between 8 and 36 tonnes (18,000 and 79,000 lb), and the height between 1 and 30 metres (3 and 98 ft).

The impact of the free fall creates stress waves that help in the densification of the soil.

The initial weight dropping has the most impact, and penetrates up to a greater depth.