Abstract
Changes of failure mechanism with increasing confinement, from tensile to shear dominated failure, is widely observed in the rupture of samples in laboratory and in rock masses in situ. However, common failure criteria typically consider only shear mechanisms. A hybrid criteria based on a sigmoid function is introduced to account for a transition from tensile to shear dominated failure with increasing confinement. When evaluated by fitting to an extensive laboratory database the sigmoid criteria does not provide a better fit compared to the Hoek-Brown failure envelope, but provides insight into rock strength controlling factors that have significant consequences with respect to the interpretation of laboratory test results. It also leads to a differentiated approach for design by considering two types of behaviour process: 1) in the inner shell, i.e. the direct vicinity of openings, the failure mode is dominated by tensile cracking leading to spalling and related geometric dilation processes and 2) in the outer shell, i.e. remote from excavations, where confinement promotes interlock, we suggest that rock masses could be significantly stronger than predicted by standard approaches.
| Original language | English |
|---|---|
| Title of host publication | Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics |
| Pages | 855-860 |
| Number of pages | 6 |
| Publication status | Published - Feb 13 2012 |
| Externally published | Yes |
| Event | 12th International Congress on Rock Mechanics of the International Society for Rock Mechanics, ISRM 2011 - Beijing, China Duration: Oct 18 2011 → Oct 21 2011 |
Publication series
| Name | Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics |
|---|
Conference
| Conference | 12th International Congress on Rock Mechanics of the International Society for Rock Mechanics, ISRM 2011 |
|---|---|
| Country | China |
| City | Beijing |
| Period | 10/18/11 → 10/21/11 |
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Keywords
- Rock properties
- Site characterization
ASJC Scopus subject areas
- Geology
- Geotechnical Engineering and Engineering Geology
Cite this
Influence of confinement dependent failure processes on rock mass strength at depth. / Valley, Benoît; Kim, Bo Hyun; Suorineni, Fidelis T.; Bahrani, Navid; Bewick, Rob P.; Kaiser, Peter K.
Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics. 2012. p. 855-860 (Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics).Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Influence of confinement dependent failure processes on rock mass strength at depth
AU - Valley, Benoît
AU - Kim, Bo Hyun
AU - Suorineni, Fidelis T.
AU - Bahrani, Navid
AU - Bewick, Rob P.
AU - Kaiser, Peter K.
PY - 2012/2/13
Y1 - 2012/2/13
N2 - Changes of failure mechanism with increasing confinement, from tensile to shear dominated failure, is widely observed in the rupture of samples in laboratory and in rock masses in situ. However, common failure criteria typically consider only shear mechanisms. A hybrid criteria based on a sigmoid function is introduced to account for a transition from tensile to shear dominated failure with increasing confinement. When evaluated by fitting to an extensive laboratory database the sigmoid criteria does not provide a better fit compared to the Hoek-Brown failure envelope, but provides insight into rock strength controlling factors that have significant consequences with respect to the interpretation of laboratory test results. It also leads to a differentiated approach for design by considering two types of behaviour process: 1) in the inner shell, i.e. the direct vicinity of openings, the failure mode is dominated by tensile cracking leading to spalling and related geometric dilation processes and 2) in the outer shell, i.e. remote from excavations, where confinement promotes interlock, we suggest that rock masses could be significantly stronger than predicted by standard approaches.
AB - Changes of failure mechanism with increasing confinement, from tensile to shear dominated failure, is widely observed in the rupture of samples in laboratory and in rock masses in situ. However, common failure criteria typically consider only shear mechanisms. A hybrid criteria based on a sigmoid function is introduced to account for a transition from tensile to shear dominated failure with increasing confinement. When evaluated by fitting to an extensive laboratory database the sigmoid criteria does not provide a better fit compared to the Hoek-Brown failure envelope, but provides insight into rock strength controlling factors that have significant consequences with respect to the interpretation of laboratory test results. It also leads to a differentiated approach for design by considering two types of behaviour process: 1) in the inner shell, i.e. the direct vicinity of openings, the failure mode is dominated by tensile cracking leading to spalling and related geometric dilation processes and 2) in the outer shell, i.e. remote from excavations, where confinement promotes interlock, we suggest that rock masses could be significantly stronger than predicted by standard approaches.
KW - Rock properties
KW - Site characterization
UR - http://www.scopus.com/inward/record.url?scp=84863057040&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84863057040&partnerID=8YFLogxK
M3 - Conference contribution
SN - 9780415804448
T3 - Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics
SP - 855
EP - 860
BT - Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics
ER -