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Experimental and numerical investigation on crack mechanism of folded flawed rock-like material under uniaxial compression
Abstract Strength, deformability and failure behaviors of rock masses are significantly affected by the widespread natural fissures that are often distributed in overlapped patterns. To investigate the failure mechanism of rock masses with overlapped fissures, uniaxial compressive tests and numerical studies were conducted on Portland cement samples containing folded flaws of different dip angles and undulation angles. The folded flaw was overlapped by several fractures at the ends. Crack initiation, propagation and coalescence were systematically investigated. Results show that there are two patterns in terms of the deformational curves of specimens containing folded flaws, i.e., the bimodal type and the single peak type. Five different failure modes were observed, including compaction, dilation, shear off crush and slip. In all specimens crack coalescence is caused by the linkage of shear cracks with the folded flaw although the failure surfaces are different because of the different failure modes of the folded flaw. After coalescence, the folded flaw can still resist a certain level of shear stress, indicating that it has shear strength, which contributes to the residual peak strength showing in the stress-displacement curves. It is also found that the failure characteristics of specimens containing folded flaws integrate the failure characteristics of rock joint under compressive shear and smooth fracture under compression, which is significantly correlated with the undulation and dip angles of the folded flaw. The findings can provide a better understanding of the failure mechanism of rock masses with folded fractures.
Highlights Established a folded flaw to investigate the failure mechanism of overlapped fissures. Numerically revealed the crack mechanism of material containing folded flaw. Undulation angle and dip angle play key roles in the failure process of folded flaw. Failure mode integrates characteristics of joint under compressive shear and smooth fracture under compression.
Experimental and numerical investigation on crack mechanism of folded flawed rock-like material under uniaxial compression
Abstract Strength, deformability and failure behaviors of rock masses are significantly affected by the widespread natural fissures that are often distributed in overlapped patterns. To investigate the failure mechanism of rock masses with overlapped fissures, uniaxial compressive tests and numerical studies were conducted on Portland cement samples containing folded flaws of different dip angles and undulation angles. The folded flaw was overlapped by several fractures at the ends. Crack initiation, propagation and coalescence were systematically investigated. Results show that there are two patterns in terms of the deformational curves of specimens containing folded flaws, i.e., the bimodal type and the single peak type. Five different failure modes were observed, including compaction, dilation, shear off crush and slip. In all specimens crack coalescence is caused by the linkage of shear cracks with the folded flaw although the failure surfaces are different because of the different failure modes of the folded flaw. After coalescence, the folded flaw can still resist a certain level of shear stress, indicating that it has shear strength, which contributes to the residual peak strength showing in the stress-displacement curves. It is also found that the failure characteristics of specimens containing folded flaws integrate the failure characteristics of rock joint under compressive shear and smooth fracture under compression, which is significantly correlated with the undulation and dip angles of the folded flaw. The findings can provide a better understanding of the failure mechanism of rock masses with folded fractures.
Highlights Established a folded flaw to investigate the failure mechanism of overlapped fissures. Numerically revealed the crack mechanism of material containing folded flaw. Undulation angle and dip angle play key roles in the failure process of folded flaw. Failure mode integrates characteristics of joint under compressive shear and smooth fracture under compression.
Experimental and numerical investigation on crack mechanism of folded flawed rock-like material under uniaxial compression
Fan, Wenchen (author) / Yang, Hui (author) / Jiang, Xueliang (author) / Cao, Ping (author)
Engineering Geology ; 291
2021-05-25
Article (Journal)
Electronic Resource
English
Crack coalescence between two non-parallel flaws in rock-like material under uniaxial compression
| British Library Online Contents | 2015
Crack coalescence between two non-parallel flaws in rock-like material under uniaxial compression
| Online Contents | 2015