Ground Improvement By High Impact Energy Dynamic Consolidation Approach

Several ground improvement approaches can be utilised when constructing over poor ground conditions. Where soft grounds are encountered near ground surface, consolidation approaches such as surcharge with Prefabricated Vertical Drains (PVD) are commonly adopted. It is known that surcharge fill placed over soft clayey ground pressurises the porewater within the soft clay, creating an excess pore pressure. This excess pore pressure drives the pore water towards the PVD which forms a drainage medium driving the excess pore fluid towards a horizontal drainage blanket.

In situations where surcharge fill is difficult to obtain near the site, or costly to be brought to site, an alternative method that utilises dynamic compaction energy to pressurise the pore water can be applied. This approach has proven to be capable of developing excess porewater pressures in soft saturated clays. When this method is applied together with PVD, the drainage of the ‘locked-in’ excess pore fluid can be expedited.

A method of dynamic compaction using rolling impact compaction approach known as High Impact Energy Dynamic Compaction (HIEDYC) is described in the paper, a process known as dynamic consolidation. Two case studies of applications of this approach in soft ground improvement, together with back analyses, are described in this paper. These case studies showed that dynamic consolidation can offer several benefits and produce better or equivalent performance as conventional treatment, including higher bearing capacity, cost saving, and shorter treatment duration.