Dynamic compaction(DC) and dynamic replacement have become generally accepted ground improvement techniques for their simplicity and cost-effectiveness. But conception of DC and dynamic replacement still have a lot of disagreement. On some foundation treatment specification revision of opportunity

it is necessary to improve the dynamic compaction and dynamic compaction replacement concepts of clarification. The distinctions between DC and dynamic replacement are: with or without filler; with or without grained soil; rammer static grounding pressure is or not greater than 80 kPa and whether formatted replacement piers. Meanwhile according to the measured data of more than 68 projects

this paper proposes the relations of dynamic displacement pier length and the energy level (top achieve 18 000 kN•m)

for the first time in China. Also it makes form for engineering personnel reference.