Insights on surface spalling of rock

Ali Tarokh, Chu Shu Kao, Ali Fakhimi, Joseph F. Labuz

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Surface spalling is a complex failure phenomenon that features crack propagation and detachment of thin pieces of rock near free surfaces, particularly in brittle rock around underground excavations when large in situ stresses are involved. A surface instability apparatus was used to study failure of rock close to a free surface, and damage evolution was monitored by digital image correlation (DIC). Lateral displacement at the free face was used as the feedback signal to control the post-peak response of the specimen. DIC was implemented in order to obtain the incremental displacement fields during the spalling process. Displacement fields were computed in the early stage of loading as well as close to the peak stress. Fracture from the spalling phenomenon was revealed by incremental lateral displacement contours. The axial and lateral displacements suggested that the displacement gradient was uniform in both directions at early loading stages and as the load increased, the free-face effect started to influence the displacements, especially the lateral displacement field. A numerical approach, based on the discrete element method, was developed and validated from element testing. Damage evolution and localization observed in numerical simulations were similar to those observed in experiments. By performing simulations in two- and three-dimensions, it was revealed that the intermediate principal stress and platen–rock interfaces have important effects on simulation of surface spalling.

Original languageEnglish (US)
Pages (from-to)391-405
Number of pages15
JournalComputational Particle Mechanics
Volume3
Issue number3
DOIs
StatePublished - Jul 1 2016

Bibliographical note

Funding Information:
Partial support was provided by the MSES/Miles Kersten Chair and the Research Council of Norway through project #215667, “Formation reinforcement for wellbore stability and sand control.”

Publisher Copyright:
© 2016, OWZ.

Keywords

  • Damage evolution
  • Digital image correlation (DIC)
  • Discrete element method (DEM)
  • Intermediate principal stress
  • Surface instability

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