Numerical analysis of group effect on dragload on piles subjected to negative skin friction

Abstract

In this paper, the group effect on dragload on pile group subjected to negative skin friction is studied. The effect of pile spacing, pile location in a group and pile number is studied using finite element program PLAXIS 3D. Single pile, 2x2 pile groups and 3x3 pile groups with pile spacing 2d and 3d existing in soft clay layer overlying dense sand layer are used in this parametric study. A layer of fill is used as a load on the layer of soft clay resulting in soil consolidation which causes increase in axial load on piles "dragload" due to negative skin friction along the piles. The results from parametric analysis showed that the group effect on dragload is relevant to pile spacing, piles number and pile location within pile groups. Results showed that the reduction in dragload due to group effect decreases with the increase in pile spacing. Results also showed that center piles had the most significant group effect on reduction of dragload followed by edge piles and corner piles respectively.

Keywords

• negative skin friction
• group effect
• pile spacing
• soft clay
• plaxis 3d