The effect of the dynamic compaction method （DCM） on the ground foundation was investigated by means of the elections of void ratio of soil

the arranging forms in the silty soil and collapsible loess ground foundation

the weight of hammer

the height of drop in the collapsible loess ground based on DCM’s reinforced principle. Some suggestions are put forward for selecting parameters

with relation to DCM in the silt and loess ground: 1.The critical void-ratio may be a standard that checks the effect of tamping; when the critical void-ratio is close to that after tamping

the solum will be compacted thoroughly. 2.The compacting points may get better effect with an equilateral triangular arrangement for a small area reinforcement; if a reinforced area is enough big

and both of those arrangements can be satisfied with engineering inquirement

of which the arrangement is suggested after economical analysis.3.The heavy hammer and the low height of drop in the collapsible loess ground is preferred when choosing DCM. These suggestions are very valuable for the promotion of the DCM and engineering practice.