Long-term effect of vertical and lateral loads on piled raft foundations: a case study

In this study, numerical analyses of connected and disconnected piled-raft foundations (PRFs) comprising a single pile, 2 × 1, 3 × 1, 2 × 2, 3 × 2, 3 × 3 and 5 × 5 pile groups subjected to different lateral loads, with a constant vertical load, have been carried out by three-dimensional finite-element analysis. Results from the analysis have been validated with reported field studies considering vertical load and reported experimental studies considering lateral load. The reported multilayered sub-soil profile has been considered for the analysis. Parametric studies in terms of the effect of variation in pile length (L/d = 20, 30, 39), spacing of piles in the pile group (S/d = 3, 5, 6), number of piles, thickness of raft (0.5, 1.2 and 2 m), variation of axial force, excess pore water pressure, bending moment and shear force along the depth of the piles for connected and disconnected PRFs have been discussed for a time period of 20 years. The horizontal connected piled-raft coefficients have been determined corresponding to the lateral deflections. A generalised equation has been predicted for the horizontal connected PRF coefficient.