A novel numerical strategy to analyse the installation and set-up effects of sand compaction piling

Sand compaction piling has been long recognized to exert considerable influence on the treated soils in various aspects. One noteworthy regard is the strength set-up or the set-up effect in soil due to the sand compaction pile installation. However, due to its complex nature, it is extremely difficult to numerically model the actual piling process, which is characterised mainly by the repeated withdrawal and re-driving of the casing tube and by the gradual expansion of the sand column. Crude simplifications of various forms had thus to be adopted in the past. This paper reports the development of an innovative approach that can replicate not only the actual sand compaction pile installation process but also the post-installation soil consolidation phenomenon. With that, the set-up effect can be realistically reflected by numerical means.