Physical and Numerical Modeling of Piled Raft Foundation in Chamkhaleh Sand

A series of laboratory large-scale model tests were conducted on piled raft founded on sand with different compaction levels. The numbers of piles are 1, 4, 5 and 9. All the piles are 40 cm in length and the slenderness ratio is 20. In these tests, the variation of load improvement ratio (LIR), load-sharing ratio (αp) and settlement ratio (SR) are reported for different relative densities and number of piles. Moreover, the variation of ultimate bearing capacity of piled raft system was investigated for different conditions. Results showed that LIR ratio will be more noticeable in loose state in comparison to dense sand, and also increasing the number of settlement reducing piles proved to decrease the SR values or increasing the SIF values in other words. In the end, a sensitivity analysis was performed to investigate the influence of each parameter in affecting the performance of the piled raft system. Based on the sensitivity analyses, relative density of soil was proven to be the most effective parameter in comparison to the number of piles. Finite element analyses have also been performed using the ABAQUS software. The numerical results from the FEM were first validated with the experimental results and then parametric study was carried out to investigate the effect of load eccentricities. It was shown that the ultimate bearing capacity of the piled raft foundation decreases significantly with an increase in the load eccentricity.