Influence of Circular Hole Diameter on Deformation and Failure of Longmaxi Shale

Han, Guansheng; Liang, Qinyuan; Bao, Ruyi; Zhou, Yu

doi:10.1007/s10706-022-02049-1

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…When the intermediate principal stress is relatively low, a large wing crack will also be formed, and its propagation degree is enough to split the sample. Based on DIC and wave velocity tests, Han et al [24] studied the effect of hole size on the deformation and failure of 90 °shale. e results found that large hole diameter (10 mm) and medium hole diameter (6 mm) were dominated by tensile failure, while a small hole diameter (2 mm) exhibited mixed tension and shear failure.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Deformation and Failure Characteristics of Shale Samples Containing Circular Hole considering the Bedding Angle Effect under Uniaxial Compression

Liang

Zhao

Zhou

et al. 2022

Mathematical Problems in Engineering

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The drilling and blasting method (DBM) is widely used in the excavation of tunnel engineering, and it is essential to first drill circular holes. This paper experimentally explored the influence of bedding angles on crack propagation of shale containing a circular hole. Specifically, the uniaxial compression tests were carried out on shale samples with a single prefabricated hole combined with digital image correlation technology (DIC) to obtain the real-time deformation process near the macro damage. The results show that the peak strength, global shear strain field, failure mode around the circular hole and macro crack failure mode of shale with prefabricated circular hole are closely related to the bedding dip angle. The strength generally increases with the decrease of the bedding angle. Two transitions of failure mode were observed at the point of 45° and 75°: tensile shear mixed failure around the circular hole (less than 45°) first transits into no damage around the circular hole (60° and 70°), and then, tensile failure occurs around the circular hole (90°). In addition, for the cases of 60° and 75°, tensile failure away from the circular hole occurs along the weak surface of bedding, while for the other cases, the tensile failure through the circular hole mainly occurs. These findings have implied that the bedding angle is one essential parameter that needs to be considered for the stability of tunnel surrounding rock.

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Section: Introductionmentioning

confidence: 99%

Investigation on the Deformation and Failure Characteristics of Shale Samples Containing Circular Hole considering the Bedding Angle Effect under Uniaxial Compression

Liang

Zhao

Zhou

et al. 2022

Mathematical Problems in Engineering

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Failure behaviors of anisotropic shale with a circular cavity subjected to uniaxial compression

Feng,

Liu,

Wang

et al. 2024

Journal of Rock Mechanics and Geotechnical Engineering

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Influences of Inclined Pre-Existing Flaw on Shale Failure Modes in Uniaxial Compression Tests

et al. 2022

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Numerous studies have focused on the mechanical properties of shale specimens to support hydraulic fracturing in shale gas engineering. However, the failure modes of shale specimens containing a pre-existing flaw are still not clear. A series of uniaxial compression tests were conducted on shale specimens containing a pre-existing flaw coupled with acoustic emission (AE) technology and a high-speed camera. A slow enough and variable loading speed scheme (0–50 kN: 0.1 kN/s, 50–100 kN: 0.05 kN/s; 100-failure: 0.02 kN/s) is adopted to allow microcracks to fully develop. The damage mechanism in the mesoscale from moment tensor inversion of the AE signals and the cracking behaviors on the macroscale were associated. Both the pre-existing flaw and the bedding layers had significant influences on the mechanical characteristics, progressive cracking, and failure modes of the shale specimens. The peak stress increases fluctuated as the bedding layer angle α increases, and the maximum and minimum values take place at α = 90° and α = 0°, respectively. In addition, the pre-existing flaw, the bedding layers, and the compression stress field jointly control the failure modes of the shale specimens. It was found that the α = 0° specimen failed due to tension splitting, the α = 30° specimen failed due to tension splitting and shear across the matrix, the α = 60° specimen failed due to shear across the shale matrix and shear along the bedding layers, and the α = 90° specimen failed due to tension along the bedding layers and shear across the shale matrix. The study can provide some references to the construction of complex crack networks in shale gas engineering.

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Influence of Circular Hole Diameter on Deformation and Failure of Longmaxi Shale

Cited by 3 publications

References 8 publications

Investigation on the Deformation and Failure Characteristics of Shale Samples Containing Circular Hole considering the Bedding Angle Effect under Uniaxial Compression

Investigation on the Deformation and Failure Characteristics of Shale Samples Containing Circular Hole considering the Bedding Angle Effect under Uniaxial Compression

Failure behaviors of anisotropic shale with a circular cavity subjected to uniaxial compression

Influences of Inclined Pre-Existing Flaw on Shale Failure Modes in Uniaxial Compression Tests

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