This paper investigated the soil improvement effects of deep dynamic compaction (DDC) on loose dry sands, in terms of peak vertical ground wave acceleration generated in DDC impact. This investigation was achieved by a series of finite element (FE) analyses, which include a validation analysis and comprehensive parametric studies. Influences on soil improvement from the following factors were studied: blow counts, impact at adjacent tamping points, and impact energy per blow. The FE analysis results indicated that most of the densification effects were achieved by the first 4 to 5 blows and further blows only imposed very limited additional densification effects. The impact at adjacent points could induce significant densification effects, and this lateral spreading improvement effect was related to both the grid spacing and the adopted impact energy per blow. Compared with those in literature, the FE analyses yielded reasonably good results. Finally, some conclusions and suggestions for DDC on loose dry sands were reached.
Abstract