Strength and Strain Quantities under Brittle Compression Process of Hard Rocks

V.A. Akinbinu¹,G.O. Oniyide¹,P.A. Adesida¹

¹Federal University of Technology Akure, Akure, Nigeria

Min. miner. depos. 2018, 12(1):61-75

https://doi.org/10.15407/mining12.01.061

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ABSTRACT

Purpose. To examine the relationships between strength properties and strain quantities associated with the brittle compression process of hard brittle rocks.

Methods. The data used in this paper were obtained from laboratory uniaxial compression tests carried out on 84 different types of hard rocks in accordance with Ulusay (2015) proposed standards. The strength properties and the strain quantities were coordinated so that each of the strain quantities or their ratios is compared individually with the strength properties of the rocks as for their relationship.

Findings. In all the cases the relationships between the strain ratios and the strength parameters are stronger than when compared with individual strain quantities. A threshold level for strain ratio Ɛvf /Ɛcd may be assumed as the limit for fracture initiation above which the rock may experience brittle fracture failure.

Originality. Scientific sources demonstrate few laboratory studies as for strength properties-strain quantities ratio. Most of the published research has been concentrated on crack damage stress (σcd) and uniaxial compressive strength (σc) of characteristic stress levels during compression. The paper has performed detailed analysis of the problem using experimental results of the relationships between strength properties and strain quantities under the deformation process of hard rocks.

Practical implications. The relationships can improve our knowledge to evaluate correctly the stability of excavations, design of stable structures such as tunnels and excavations for mining and civil engineering purposes.

Keywords: relationships, deformation process, hard brittle rocks, strength properties, stability of excavations

REFERENCES

Akinbinu, V.A. (2017). Relationship of Brittleness and Fragmentation in Brittle Compression. Engineering Geology, (221), 82-90.
https://doi.org/10.1016/j.enggeo.2017.02.029

Andersson, J.C., Martin, C.D., & Stille, H. (2009). The Äspö Pillar Stability Experiment: Part II – Rock Mass Response to Coupled Excavation-Induced and Thermal-Induced Stresses. International Journal of Rock Mechanics and Mining Sciences, 46(5), 879-895.
https://doi.org/10.1016/j.ijrmms.2009.03.002

Bieniawski, Z.T. (1967). Mechanism of Brittle Fracture of Rock. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 4(4), 395-430.
https://doi.org/10.1016/0148-9062(67)90032-0

Cai, M., Kaiser, P., Tasaka, Y., Maejima, T., Morioka, H., & Minami, M. (2004). Generalized Crack Initiation and Crack Damage Stress Thresholds of Brittle Rock Masses Near Underground Excavations. International Journal of Rock Mechanics and Mining Sciences, 41(5), 833-847.
https://doi.org/10.1016/j.ijrmms.2004.02.001

Eberhardt, E., Stead, D., & Stimpson, B. (1999). Quantifying Progressive Pre-Peak Brittle Fracture Damage in Rock During Uniaxial Compression. International Journal of Rock Mechanics and Mining Sciences, 36(3), 361-380.
https://doi.org/10.1016/s0148-9062(99)00019-4

Katz, O., & Reches, Z. (2004). Microfracturing, Damage, and Failure of Brittle Granites. Journal of Geophysical Research: Solid Earth, 109(B1), 1-13.
https://doi.org/10.1029/2002jb001961

Kim, J.-S., Lee, K.-S., Cho, W.-J., Choi, H.-J., & Cho, G.-C. (2014). A Comparative Evaluation of Stress-Strain and Acoustic Emission Methods for Quantitative Damage Assessments of Brittle Rock. Rock Mechanics and Rock Engineering, 48(2), 495-508.
https://doi.org/10.1007/s00603-014-0590-0

Nicksiar, M., & Martin, C.D. (2012). Evaluation of Methods for Determining Crack Initiation in Compression Tests on Low-Porosity Rocks. Rock Mechanics and Rock Enginee-ring, 45(4), 607-617.
https://doi.org/10.1007/s00603-012-0221-6

Palchik, V. (2009). Mechanical Behavior of Carbonate Rocks at Crack Damage Stress Equal to Uniaxial Compressive Strength. Rock Mechanics and Rock Engineering, 43(4), 497-503.
https://doi.org/10.1007/s00603-009-0042-4

Palchik, V. (2012). Is there Link between the Type of the Volumetric Strain Curve and Elastic Constants, Porosity, Stress and Strain Characteristics? Rock Mechanics and Rock Engineering, 46(2), 315-326.
https://doi.org/10.1007/s00603-012-0263-9

Pérez Hidalgo, K., & Nordlund, E. (2012). Comparison Between Stress and Strain Quantities of the Failure – Deformation Process of Fennoscandian Hard Rocks Using Geological Information. Rock Mechanics and Rock Engineering, 46(1), 41-51.
https://doi.org/10.1007/s00603-012-0242-1

Rigopoulos, I., Tsikouras, B., Pomonis, P., & Hatzipanagiotou, K. (2011). Microcracks in Ultrabasic Rocks Under Uniaxial Compressive Stress. Engineering Geology, 117(1-2), 104-113.
https://doi.org/10.1016/j.enggeo.2010.10.010

Stacey, T.R. (1981). A Simple Extension Strain Criterion for Fracture of Brittle Rock. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 18(6), 469-474.
https://doi.org/10.1016/0148-9062(81)90511-8

Stefanov, Y.P., Chertov, M.A., Aidagulov, G.R., & Myasni-kov, A.V. (2011). Dynamics of Inelastic Deformation of Porous Rocks and Formation of Localized Compaction Zones Studied by Numerical Modeling. Journal of the Mechanics and Physics of Solids, 59(11), 2323-2340.
https://doi.org/10.1016/j.jmps.2011.08.002

Ulusay, R. (2015). The ISRM Suggested Methods for Rock Characterization, Testing and Monitoring: 2007 – 2014. Ankara, Turkey: Pergamon Press Ltd.
https://doi.org/10.1007/978-3-319-07713-0

Xue, L., Qin, S., Sun, Q., Wang, Y., Lee, L.M., & Li, W. (2013). A Study on Crack Damage Stress Thresholds of Different Rock Types Based on Uniaxial Compression Tests. Rock Mechanics and Rock Engineering, 47(4), 1183-1195.
https://doi.org/10.1007/s00603-013-0479-3

Xue, L., Qi, M., Qin, S., Li, G., Li, P., & Wang, M. (2014). A Potential Strain Indicator for Brittle Failure Prediction of Low-porosity Rock: Part I – Experimental Studies Based on the Uniaxial Compression Test. Rock Mechanics and Rock Engineering, 48(5), 1763-1772.
https://doi.org/10.1007/s00603-014-0675-9

Yang, S.-Q. (2016). Experimental Study on Deformation, Peak Strength and Crack Damage Behavior of Hollow Sandstone Under Conventional Triaxial Compression. Engineering Geology, (213), 11-24.
https://doi.org/10.1016/j.enggeo.2016.08.012