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 language | English (US) |
|---|---|
| Title of host publication | 4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 |
| Publisher | International Society for Rock Mechanics |
| Pages | 235-238 |
| Number of pages | 4 |
| Volume | 2017-May |
| ISBN (Electronic) | 9791156103158 |
| State | Published - Jan 1 2017 |
| Event | 4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 - Jeju, Korea, Republic of Duration: May 10 2017 → May 13 2017 |
Other
| Other | 4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 |
|---|---|
| Country | Korea, Republic of |
| City | Jeju |
| Period | 5/10/17 → 5/13/17 |
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Keywords
- Fracture toughness
- Loading rate
- Strength
- Time dependent
ASJC Scopus subject areas
- Geotechnical Engineering and Engineering Geology
- Geophysics
Cite this
Loading rate dependency of strength and fracture toughness of rocks. / Ko, Tae Young; Kemeny, John M; Jeon, Seokwon.
4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017. Vol. 2017-May International Society for Rock Mechanics, 2017. p. 235-238.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Loading rate dependency of strength and fracture toughness of rocks
AU - Ko, Tae Young
AU - Kemeny, John M
AU - Jeon, Seokwon
PY - 2017/1/1
Y1 - 2017/1/1
N2 - 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.
AB - 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.
KW - Fracture toughness
KW - Loading rate
KW - Strength
KW - Time dependent
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M3 - Conference contribution
VL - 2017-May
SP - 235
EP - 238
BT - 4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017
PB - International Society for Rock Mechanics
ER -