Ganyu por area in Lianyungang in Jiangsu Province was hydraulically filled with the dredging earthworks from the channel and harbor which were composed of two layers of soils

i.e.clay and sand.As hydraulic filling with the above soils together

the sand-clay mixing foundation was deposited.In this case

the dynamic compaction method was adopted to improve the bearing capacity and uniformity of the foundation.The change of single point′s compaction settlement

excess pore pressure and soil strength after compaction were measured first

and then

the strengthened depth and horizontal influence area was discussed later.The results showed that the modification coefficient of effective improvement depth ranged from 0.35 to 0.5

and improvement zones were not consistent in respect of pore water pressure and soil strength

in other words

the influenced range of pore water pressure is larger than that of soil strength.These result could deepen the understanding of the dynamic compaction method in this kind of foundation.