The settlement behavior of piled raft in clay soils

The settlement behavior of a square piled raft in clay soil was investigated using numerical analysis. The emphasis was on quantifying the reduction of the average and differential settlements in soft and stiff clay soils. To obtain the detailed information on the piled raft, a nonlinear three-dimensional finite element analysis with pilesoil slip interface model was performed for various pile positions, pile numbers, pile lengths under the raft and different loading types. Based on the results obtained, the settlement aspects for an efficient design of piled rafts subjected to vertical loading are discussed for soft and stiff clay soils. It is found that the variation of reduction ratio (s _PR,avg/s _UR,avg) of soft clay was relatively greater than that of stiff clay, whereas the reduction ratio of soft clay was relatively smaller than that of stiff clays. It is also found that the required pile group-raft area ratio (A _g/A _r) for minimizing differential settlement in soft clay was slightly larger than that of stiff clay in the same pile array.