What it is:
Dynamic replacement (or dynamic substitution) provides an alternative to dynamic compaction when soil cannot be compacted. Filler material must then be incorporated, usually representing 10 to 25 percent of the soil mass treated.
How it works:
The equipment used is similar to that for dynamic compaction. A conventional crane drops a 10 to 20-tonne steel weight from a height of 10 to 25 metres. With or without pre-excavation, the technique uses alternate phases of ramming and filling of large-diameter footprints by front-end loader.
Why it’s used:
The added material with a high shear modulus and replacement rate improves structural stability and reduces potential liquefaction of the natural soil, as well as soil drainage. Bearing capacity is increased and settling is reduced.