Arabian Journal for Science and Engineering

, Volume 44, Issue 5, pp 4613–4627 | Cite as

Laboratory Study on Load Carrying Capacity of Pile Group in Unsaturated Clay

  • Raid R. Al-Omari
  • Mohammed Y. FattahEmail author
  • Abbas M. Kallawi
Research Article - Civil Engineering


In this study, an attempt is made to investigate the load transfer in pile groups constructed in saturated and unsaturated soil using aluminum model piles of \(20\times 20\) mm in cross section and 200 mm in length with six group configurations, single, \(2\times 1\), \(3\times 1\), \(2\times 2\), \(3\times 2\), and \(3\times 3\), groups in addition to pull-out test. The samples are prepared at three different soil properties: two models with the same degree of saturation and two with different dry unit weights and the third is unsaturated soil model with. A relationship between the soil suction and water content is introduced using a digital monitor, accompanied by eight suction probes planted in CBR molds. This relationship is used to predict the value of suction when conducting tests on models of the unsaturated soil. Further, the soil suction is measured using a filter paper method. Results of ultimate load capacity obtained from the load–displacement curves reveal an increase in the ultimate load with increasing the number of piles in the group for the same soil properties, and also an increase in the soil dry unit weight. Further, the results indicate an increase in pile capacity when the soil becomes in unsaturated state compared with saturated soil for the same pile group tested. On the other hand, the pull-out test gives a maximum load carrying capacity when the single pile tested was in saturated soil with high dry density, and minimum results are obtained when tested in unsaturated condition with the percentage of increase being about 463 and 34% for two saturated soils, compared with that for unsaturated soil.


Pile Group Unsaturated clay Suction Bearing capacity 


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  1. 1.
    Georgiadis, K.: Development, implementation and application of partially saturated soil models in finite element analysis. Ph.D. Thesis, Imperial College of Science, Technology and Medicine, University of London (2003)Google Scholar
  2. 2.
    Vanapalli, S.K.; Taylan, Z.N.: Design of single piles using the mechanics of unsaturated soils. Int. J. GEOMATE 2(1 (Sl. No. 3)), 197–204 (2012). JapanGoogle Scholar
  3. 3.
    Mohsen, I.M.: Behavior of single pile in unsaturated clay soils. M.Sc. Thesis, Building and Construction Engineering Department, University of Technology, Iraq (2012)Google Scholar
  4. 4.
    Fattah, M.Y.; Salim, N.M.; Mohsin, I.M.: Behavior of single pile in unsaturated clayey soils. Eng. Technol. J. 32(3), 763–787 (2014)Google Scholar
  5. 5.
    Vanapalli, S.K.; Mohamed, F.M.O.: Bearing capacity and settlement of footings in unsaturated sands. Int. J. GEOMATE 5(1), 595–604 (2013)Google Scholar
  6. 6.
    Oh, W.T.; Vanapalli, S.K.: Interpretation of the bearing capacity of unsaturated fine-grained soil using the modified effective and the modified total stress approaches. Int. J. Geomech. ASCE 13(6), 769–778 (2013)CrossRefGoogle Scholar
  7. 7.
    Xu, Y.; Cao, L.: Fractal representation for effective stress of unsaturated soils. Int. J. Geomech. ASCE (2014).,04014098
  8. 8.
    Hamilton, M.: Pile–soil interaction in unsaturated soil conditions, University of New Hampshire. (2014)
  9. 9.
    Chung, S.H.; Yang, S.R.: Numerical analysis of small-scale model pile in unsaturated clayey soil. Int. J. Civ. Eng. 15(6), 877–886 (2017)CrossRefGoogle Scholar
  10. 10.
    ASTM D 422-00: Standard test method for particle size-analysis of soils, American Society for Testing and MaterialsGoogle Scholar
  11. 11.
    Fattah, M.Y.; Yahya, A.Y.; Al-Hadidi, M.T.; Ahmed, B.A.: Effect of salt content on total and matric suction of unsaturated soils. Eur. Sci. J. 9(9), 228–245 (2013)Google Scholar
  12. 12.
    ASTM Standard D698: Standard test methods for laboratory compaction characteristics of soil using standard effort. ASTM International, West Conshohocken, PA (2007)Google Scholar
  13. 13.
    Bicalho, K.V.; Cupertino, K.F.; Bertolde, A.I.: Evaluation of the suction calibration curve for Whatman 42 filter paper. In: Caicedo, L., et al. (eds.) Advances in Unsaturated Soils. Taylor and Francis Group, London (2013)Google Scholar
  14. 14.
    ASTM-D-5298-03: Standard test method for measurement of soil potential (suction) using filter paper. In: Annual Book of ASTM Standards, Vol. 04.08, Soil and Rock, pp. 1–6Google Scholar
  15. 15.
    Fredlund, D.G.; Gan, J.K.M.; Gallen, P.: Suction measurements on compacted till specimens and indirect filter paper calibration technique. Transp. Res. Board Transp. Res. Record 1481, 3–9 (1995)Google Scholar
  16. 16.
    Likos, W.J.; Lu, N.: Filter paper technique for measuring total soil suction. Transportation Research Record 1786, Paper No. 02-2140, pp. 120-128 (2002)Google Scholar
  17. 17.
    EM 1110-2-2906.: (1991).: Design of pile foundations. Engineer Manual. Department of the Army, U.S. Army Corps of Engineers Washington, DC, pp. 20314–1000 (1991)Google Scholar
  18. 18.
    Fellenius, B.H.: What Capacity Value to Choose from the Results of a Static Loading Test. Fulcrum, Deep Foundation Institute, New Jersey (2001)Google Scholar
  19. 19.
    Fellenius, B.H.: Basics of Foundation Design, Electronic edn (2006).
  20. 20.
    Lambe, T.W.; Whitman, R.V.: Soil Mechanics. Wiley, New York (1979)Google Scholar
  21. 21.
    Prakash, S.; Sharma, H.D.: Pile Foundations in Engineering Practice. Wiley, New York (1990)Google Scholar
  22. 22.
    Murthy, V.N.S.: Geotechnical Engineering: Principles and Practices of Soil Mechanics and Foundation Engineering. Marcel Dekker, Inc., New York (2003)Google Scholar
  23. 23.
    Bowles, J.E.: Foundation Analysis and Design, 5th edn. McGraw-Hill Book Companies, Inc., New York (1996)Google Scholar
  24. 24.
    Huat, B.B.K.; Ali, F.H.; Abdullah, A.: Field and laboratory suction–soil moisture relationship of unsaturated residual soils. Am. J. Environ. Sci. 1(1), 34–40 (2005)CrossRefGoogle Scholar
  25. 25.
    Daichao, S.; Annan, Z.; Fredlund, D.G.: Shear strength criteria for unsaturated soils. Geotech. Geol. Eng. 2(9), 145–159 (2011)Google Scholar
  26. 26.
    Fredlund, D.G.; Morgernstern, N.R.; Widger, R.A.: The shear strength of unsaturated soils. Can. Geotech. J. 15(3), 316–321 (1978)CrossRefGoogle Scholar
  27. 27.
    Fredlund, D.G.; Xing, A.; Fredlund, M.D.; Barbour, S.L.: The relationship of the unsaturated shear strength to the soil-water characteristic curve. Can. Geotech. J. 33(3), 440–448 (1996)CrossRefGoogle Scholar
  28. 28.
    Vanapalli, S.K.; Fredlund, D.G.; Barbor, S.L.: A rational for an extended soil- water characteristic curve. In: 49th Canadian Geotechnical Conference of the Canadian Geotechnical Society, St. John Newfoundland, Canada (1996)Google Scholar
  29. 29.
    Vanapalli, S.K.; Fredlund, D.G.: Comparison of different procedures to predict unsaturated soil shear strength. Adv. Unsaturated Geotech. ASCE Geotech. Spec. Publ. 99, 195–221 (2000)CrossRefGoogle Scholar
  30. 30.
    Tomlinson, M.J.: Pile Design and Construction Practice, pp. 2–6. Boundary Row, London (1994)Google Scholar

Copyright information

© King Fahd University of Petroleum & Minerals 2018

Authors and Affiliations

  • Raid R. Al-Omari
    • 1
  • Mohammed Y. Fattah
    • 2
    Email author
  • Abbas M. Kallawi
    • 3
  1. 1.Civil Engineering Department, College of EngineeringAl-Nahrain UniversityBaghdadIraq
  2. 2.Civil Engineering DepartmentUniversity of TechnologyBaghdadIraq
  3. 3.University of BaghdadBaghdadIraq

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