Influence of Two Cross-Flaws Geometry on the Strength and Crack Coalescence of Rock-Like Material Specimens under Uniaxial Compression
Publication: International Journal of Geomechanics
Volume 20, Issue 8
Abstract
Cross-flaws are very common in natural rocks. To date, the understanding of the failure process of rocks with cross-flaws is very limited. In this research, we study the influence of the cross-flaws geometry on the rock strength and coalescence modes with rock-like specimens. In this work, three groups of specimens with pre-existing cross-flaws are investigated: two aligned cross-flaws, two step cross-flaws, and two collinear primary flaws. The crack propagation and strength of specimens containing two parallel flaws are also studied to compare the results with those of specimens with cross-flaws. The results demonstrate that the cross-flaw geometry influences the rock bridge coalescence patterns in rock-like specimens. Specimens with two aligned cross-flaws and two step cross-flaws coalesce with tensile cracks in the rock bridge areas, while specimens with two collinear primary flaws coalesce with shear cracks. Specimens containing two cross-flaws may have a higher uniaxial compressive strength than specimens containing two parallel flaws, and the number of specimens with a higher uniaxial compressive strength is influenced by the cross-flaws geometry in the different groups. The cross-flaws geometry influences the strength of the specimens. In this research, specimens in the group containing two aligned cross-flaws have the highest mean uniaxial compressive strength, and specimens in the group with two step cross-flaws have the lowest strength.
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Acknowledgments
This paper was funded by the National Natural Science Foundation of China (Nos. 51879151, 51739007, and 51879153).
Notation
The following symbols are used in this paper:
- α
- angle between the primary flaws (i.e., Flaws ① or ③) and the horizontal direction;
- β
- angle between the primary and secondary flaws; and
- |τ(θr)max|
- maximum shear stress (absolute value).
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Published In
International Journal of Geomechanics
Volume 20 • Issue 8 • August 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Mar 29, 2019
Accepted: Mar 5, 2020
Published online: Jun 9, 2020
Published in print: Aug 1, 2020
Discussion open until: Nov 9, 2020
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