Cover
Vol. 1 No. 1 (2025)

Published: December 14, 2025

Pages: 21-31

Research Article

Numerical Analysis of Soft Clay Improvement Using Ordinary and Geogrid-Encased Stone Columns with PLAXIS 3D

Marwah Fadhil Al-Ghaith 1 Osamah S. Abdulkareem Al-Salih Samoel Mahdi Saleh
1Civil Engineering Department, Engineering College, Basrah University, Iraq
History
  • Received: August 20, 2025
  • Revised: September 29, 2025
  • Accepted: November 15, 2025
  • Available Online: December 14, 2025

Abstract

This study investigates the application of Ordinary Stone Columns (OSCs) and Geogrid-Encased Stone Columns (GESCs) in enhancing the properties of soft clay soils through numerical analysis using PLAXIS 3D (version 2024). The study contrasts numerical findings with two well-researched field case studies: one in Korea and one in Iraq. The analyses were calibrated using the Mohr-Coulomb and Hardening Soil models, and settlement responses were assessed for different reinforcement scenarios, including untreated soil, OSCs, and GESCs. The results show a strong match between PLAXIS 3D simulations and field measurements, confirming the method's reliability. In the floating case (in Iraq), OSCs increased load-bearing capacity by about 21%, while GESCs improved it by around 30% compared to untreated soft clay. For the end-bearing case (in Korea), even greater enhancements were recorded, with OSCs increasing the bearing capacity by nearly doubling it and GESCs by almost 2.5 times compared to untreated soil. Geogrid encasement is presented as significantly improving settlement control and bearing capacity, with PLAXIS 3D proving to be an important design aid in geoground improvement systems.

Keywords

References

  1. Barksdale, R.D. and R.C. Bachus, Design and construction of stone columns, vol. I. 1983, Turner- Fairbank Highway Research Center.
  2. Bergado, D.T., Soft ground improvement: in lowland and other environments. 1996.
  3. Kempfert, H.-G. and B. Gebreselassie, Excavations and foundations in soft soils. 2006: Springer.
  4. Fattah, M. Y. and Q. G. Majeed, Behaviour of Encased Floating Stone Columns. Engineering and Technology Journal, 2009. 27(7): p. 1404-1421.
  5. Fattah, M.Y., B.S. Zabar, and H.A. Hassan, Experimental Analysis of Embankment on Ordinary and Encased Stone Columns. International Journal of Geomechanics, 2016. 16(4).
  6. Kadhim, S.T., Stability analysis of geotextile encased sand columns, in pH. D. 2016.
  7. Dheerendra Babu, M.R., S. Nayak, and R. Shivashankar, A Critical Review of Construction, Analysis and Behaviour of Stone Columns. Geotechnical and Geological Engineering, 2012. 31(1): p. 1-22.
  8. Marto, A., et al., Performance analysis of reinforced stone columns using finite element method. 2013. 18: p. 315-323.
  9. Basack, S. and S. Nimbalkar, Load-Settlement Characteristics of Stone Column Reinforced Soft Marine Clay Deposit: Combined Field and Numerical Studies. Sustainability, 2023. 15(9).
  10. Bhatia, P. and M. Hasan. Three-Dimensional Numerical Investigation of Stone Columns Encased with Geosynthetic in Very Soft Soil. in Indian Geotechnical Conference. 2024. Springer.
  11. Demir, A., BEARING CAPACITY and BULGING BEHAVIOR of GEOGRID ENCASED STONE COLUMNS. Selcuk University Journal of Engineering, Science and Technology, 2016. 4(2): p. 131-131.
  12. K. Grundbau, https://www.keller.com/expertise/techniques/vibro- compaction.
  13. Kwa, S., E. Kolosov, and M.J.S.s.U.n.Z.i.S. Fattah, Ground improvement using stone column construction encased with geogrid. 2018(3): p. 49- 59.
  14. RamazanBorujerdi, A.J.J.o.S.U.E., Analysis of Geosynthetic-Reinforced Stone Piles-Supported Embankments. 2023. 3(1): p. 35-41.
  15. Thakur, A., S. Rawat, and A.K. Gupta, Experimental and numerical modelling of group of geosynthetic-encased stone columns. Innovative Infrastructure Solutions, 2020. 6(1).
  16. Abbawi, Z.W., Proposed Techniques for Improving Soft Soil Underneath a Ballasted Track, in Ph. D. thesis 2010, University of Technology: Iraq.
  17. Manual, P.D.R. https://bentleysystems.service-now.com/community?id=kb_article&sysparm article KB0107989.
  18. Al-Qayssi, M.R., Unreinforced and reinforced behavior of single and groups of granular piles, in pH. D. Thesis. 2001, Civil Engineering Faculty of the Military College of Engineering: Iraq.
  19. Yoo, C. and D. Lee, Performance of geogrid- encased stone columns in soft ground: full-scale load tests. Geosynthetics International, 2012. 19(6): p. 480-490.
  20. Yousif, M.A., Analysis of Stone Columns using Finite Element Technique, in pH. D. 2003, Building and Construction, Engineering Department, University of Technology: Iraq.