ABSTRACT
Reinforcement of soft soil with vertical rigid piles is now a widespread technique for both embankments and floor slabs (Simon & Schlosser 2006). A famous example is the Rion-Antirion Bridge in Greece, with its piers put on a granular platform, installed on a network of vertical steel piles that reinforces the soft soil on the sea bed (Garnier & Pecker 1999, Rault et al. 2006). In the granular mattress, installed at the top of the reinforced soil, “arching” develops in order to transfer the load through the piles (Fig. 1). However, the understanding of the “arching” mechanism is not complete, as many parameters play a role, such as the mean grain size d50, the maximum grain size dmax the height of the mattress HM, the pile spacing s, the area ratio α (proportion of pile area in an elementary mesh) or the grain size distribution.
