The elasto-plastic analysis of normal stress increment and stress paths for the bore wall of rock-socketed pile

Jiang Xu, Guoliang Dai, Desheng Zhu, Weimingweiming Gong, Ranjith Pathegama Gamage, Asadul Haque

Research output: Contribution to journalArticleResearchpeer-review

Abstract

As the relative displacement of the pile-rock interface increases, the sliding and mutual squeezing between asperities of the pile-rock interface causes the normal stress increases by Δσn with the normal displacement. All prevalent theoretical methods use the elastic solution of cylindrical cavity expansion in an infinite medium to calculate the normal stress increment Δσn during an increase in the relative displacement of the pile-rock interface. To further optimize the calculation method for the normal stress increment Δσn of the bore wall of the rock-socketed pile, this study conducts an elasto-plastic analysis of the stress and displacement fields during expansion using cavity expansion theory and the Hoek-Brown failure criterion. Based on the obtained elasto-plastic solution, some validation cases are represented to illustrate the difference between the results of Δσn due to both elastic and elasto-plastic solutions. When the normal displacement is greater than the critical normal displacement and the rock of the bore wall yields, the elastic method overestimates the Δσn and shear strength at the pile-rock interface, which renders the design unsafe. Three modifications are then proposed to calculate the shear strength at the pile-rock interface. After that, parametric studies are conducted to examine the effects of geometric and rock-related parameters on the Δσn of the bore wall. Finally, the radial and tangential stress paths and possible crack formation of rock of the bore wall during expansion are discussed.

Original languageEnglish
Article number1464
Number of pages14
JournalArabian Journal of Geosciences
Volume14
Issue number15
DOIs
Publication statusPublished - 23 Jul 2021

Keywords

  • Cavity expansion theory
  • Elasto-plastic analysis
  • Hoek-Brown failure criterion
  • Normal stress increment
  • Rock-socketed pile
  • Stress paths and the possible crack formation process

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