Settlement behaviour of a pile raft subjected to vertical loadings in multilayered soil

Abstract

The performances of a piled raft system in terms of serviceability and load-carrying capacity have been reviewed. The settlement behaviour of a square-piled raft in a layered soil is investigated using numerical analysis. The emphasis is given on quantifying the reduction of the average and the differential settlements of the raft in layered soil. A 3D finite element analysis using a commercial software called PLAXIS 3D (Version 2) is performed for various pile positions, pile numbers and pile lengths under the raft subjected to a uniform vertical loading. The settlement aspects for an efficient design of a piled raft subjected to vertical loadings have been addressed. It is found that the required piled group-raft area ratio (Bg/Br) for minimising the differential settlement of a raft in a layered soil should be within a range of 0.4 to 0.6.