Numerical Study of the Influence of the Raft-Soil Stiffness Ratio on the Behavior of the Piled Raft Foundation Located on Sandy Soil

Document Type : Civil Article

Authors

Department of Civil Engineering, Mahabad Branch, Islamic Azad University, Mahabad, Iran

Abstract

The Piled raft foundation (PRF) is a combination of pile and raft that provides adequate bearing capacity under the allowable settlement. In this article, finite element method and PLAXIS 3D software is used to investigate the behavior of piled raft foundation system located on sandy soils under vertical load. In the finite element program 27 numerical models simulated and analyzed for rafts without piles and reinforced with piles. The effect of raft-soil stiffness, number, spacing, and piles arrangement on the general load- displacement behavior, improvement of bearing capacity, reduction of settlement and the Share of load distribution between raft and piles group discussed. The results shown that increasing the soil- raft stiffness and the number of piles has the least effect on the general mechanism of the load-settlement curve. Increasing the raft-soil stiffness improved the bearing capacity and settlement reduction ratio by an average of 19% and 23%, respectively, and the share of load carried by the raft by about 5% reduced. In addition, increasing the number of piles improved the bearing capacity and settlement reduction ratio by about 71% and 55%, respectively, and the share of load carried by the raft by an increasing amount of 41% reduced. Also, the arrangement and spacing of piles had a small effect of about 4% on the general load-settlement behavior, the share of load sharing between rafts and piles, improving the bearing capacity and reducing settlement.

Keywords

Main Subjects

References

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Journal of Modeling in Engineering
Volume 23, Issue 82
October 2025
Pages 267-279

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History

  • Receive Date: 21 November 2024
  • Revise Date: 06 March 2025
  • Accept Date: 08 April 2025

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