Numerical analysis of negative skin friction on piles in soft clay

Yasser M. El-Mossallamy, Ashraf M. Hefny, Magdy A. Demerdash, Mohamed S. Morsy

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Negative skin friction is considered one of the problems in the design of piled foundations in soft soil. The negative skin friction induces an additional compressive force on the pile called the dragload as well as, an additional pile movement called the downdrag. Ignoring the effect of negative skin friction in the design of piles leads to structural, and serviceability problems. The dragload depends on various factors such as, pile characteristics (method of installation, material, and surface treatment), soil properties (shear strength and compressibility), pile–soil relative movement, and degree of consolidation. In this paper, an axisymmetric finite element model was used to simulate, and analyze the pile–soil interaction problem of negative skin friction. The soft soil was simulated by the double hardening soil model, and the pile was described by a linear elastic model. A field case study for two instrumented end bearing driven pipe precast concrete piles in Bangkok soft clay was back analyzed. The various approaches to model the pile element, and load configurations were analyzed, and compared. An extensive parametric study was carried out to investigate the effect of different factors on the dragload value, neutral plane location, slip length, and pile movement.

Original languageEnglish
Pages (from-to)68-76
Number of pages9
JournalHBRC Journal
Issue number1
Publication statusPublished - 2013
Externally publishedYes


  • Downdrag
  • Dragload
  • Neutral plane
  • Pile–soil interaction
  • Slip length

ASJC Scopus subject areas

  • Environmental Engineering
  • Building and Construction
  • Civil and Structural Engineering
  • Geotechnical Engineering and Engineering Geology
  • Architecture
  • Materials Science (miscellaneous)
  • Urban Studies


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