NUMERICAL MODELLING OF DISCONNECTED PILED-RAFT FOUNDATION SYSTEMS SETTLEMENT WITH AN EMPHASIS ON NEW DEFINITION OF THESE SYSTEMS WITH HYBRID SYSTEM

The most extensive application of raft foundations, with pile when the raft alone can be enough resistance against the incoming load, to avoid large settlements of foundation, prevents the formation of differential settlement, pile group under the raft has been used. In this study, foundation deformation, maximum, average and differential settlements of foundation in piled-raft foundations systems under static loading in sandy soil using finite element modeling to various arrangements of piles and different composite systems regarding connection of raft and piles, has been studied and analyzed. The design of a pile group is usually based on a high safety of factor for the piles and the main design criterion is the group's load capacity. Plaxis 3D foundation finite element software version 1.6 is used to model piled-raft systems. Obtained results indicates that using the connected and disconnected piles as combined leads to very appropriate combined system performance on reduction the maximum and differential settlement of raft foundation.