small-scale model test and three-dimensional analysis of pile-raft foundation on medium-dense sand

the pile-raft foundation is a combination of a raft foundation with piles. pile-raft foundation has been widely designed, assuming all structure loads to be transferred to piles without considering contribution of the load taken by contact surface between raft and soil. methods of analysis currently used in practice are based upon relatively conservative assumptions of soil behavior or on the less realistic soil-structure interaction. in this study the bearing -settlement behavior of combined pile-raft foundations on medium dense sand was investigated. 1g physical model test was performed on a circular rigid raft underpinned with four model piles. numerical simulation was also carried out on the model test, using flac-3d, to show compatibility of the numerical analysis with the test. the obtained results showed very good accuracy of the numerical method used in this study as long as the applied load does not exceed the working load, while the performance of numerical model was relatively good for the loads beyond working load.