Parametric study for settlement and strength analysis of under-reamed grouped piled raft foundation under static load condition

For current work, numerical analysis was carried out for one of the sites in southwest zone of Gujarat. The structure consists of G.F.+ four storey building with 11 m x 21 m footprint. The foundation consists of three rafts of equivalent thickness. For sake of simplicity, the analysis was restricted to one of the rafts supported by under reamed piles. The geometry and dimensions of the under reamed pile were kept as per relevant Indian standard code. Comparison has been made to understand the settlement response for various pile group combination. The FE model consist of (a) 7 x 2, (b) 6 x 2, (c) 5 x 2, (d) 4 x 2, (e) 3 x 2 under reamed pile group with equal height and diameter as well as uniform raft thickness. The soil data where estimated based on the observed SPT N recorded through three boreholes. The results show significant decrease in settlement value was observed for under reamed pile configuration when compared to conventional pile group.