Loading rate dependency of strength and fracture toughness of rocks

Tae Young Ko, John M Kemeny, Seokwon Jeon

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Strength and fracture toughness of rocks are important parameters in various fields of rock engineering application. Many researchers have reported that strength and fracture toughness of rocks increase with loading rate. The loading rate is related to time-dependent behaviors of rocks and it important factor for assessing long-term stability of underground structures. In this study, Brazilian tension tests for tensile strength and short beam compression tests for shear strength were carried out with different loading rates ranging from 0.01 MPa/s to 10 MPa/s using Coconino sandstone. Similarly, mode I, mode II, mode III fracture toughness tests were performed with the same loading rate of strength tests. Grooved disc specimens, short beam compression specimen, and circumferentially notched cylindrical specimens were employed for fracture toughness tests. The results show that both rock strength and fracture toughness are proportional to 1/(n+1) th power of loading rate, where the parameter n represent subcritical crack growth due to stress corrosion. The values of n are almost constant regardless of loading configuration. Also, literature reviews show that the values of n are different form rock types. Thus, the parameter n can be considered a material constant of rocks.

Original languageEnglish (US)
Title of host publication4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017
PublisherInternational Society for Rock Mechanics
Pages235-238
Number of pages4
Volume2017-May
ISBN (Electronic)9791156103158
StatePublished - Jan 1 2017
Event4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 - Jeju, Korea, Republic of
Duration: May 10 2017May 13 2017

Other

Other4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017
CountryKorea, Republic of
CityJeju
Period5/10/175/13/17

Keywords

  • Fracture toughness
  • Loading rate
  • Strength
  • Time dependent

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Geophysics

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  • Cite this

    Ko, T. Y., Kemeny, J. M., & Jeon, S. (2017). Loading rate dependency of strength and fracture toughness of rocks. In 4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 (Vol. 2017-May, pp. 235-238). International Society for Rock Mechanics.