Optimizing the Bearing Capacity of Tapered Piles in Realistic Scale Using 3D Finite Element Method

This study aims to investigate the behavior of tapered and their counterpart cylindrical piles using a commercially available 3D finite element software. Three series of tapered and cylindrical piles with the same volume are modeled. In each series, five single piles are modeled, one cylindrical and four tapered. Piles embedded in sandy soils with different internal friction and dilatancy angles are considered. After twice analysis of end and frictional bearing capacity of each pile, the load-settlement diagram is obtained. The end and skin bearings are then computed using various methods. The results are then compared to obtain the optimum taper angle for maximum bearing capacity of tapered piles. It is found that the optimal tapering angle reaches to 1.2° in dense sands. A parametric study is also performed. The results indicated that by increasing internal friction and dilatancy angles of soil, the bearing capacity of tapered piles in sand is utmost increased 11 % compared to that for the same volume cylindrical pile.