An Experimental Investigation on the Characteristics of Excavation‐Induced Failure of Rocks Surrounding a Shaft

A series of true triaxial compression (TTC) tests was conducted on granite specimens to investigate their fracture behavior. The granite was sampled from a 1500‐m‐deep exploration borehole located on the Sanshandao gold field in Shandong Province, China, where a 1915‐m deep vertical shaft was planne...

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Bibliographic Details
Published in:Advances in civil engineering 2024-12, Vol.2024 (1)
Main Authors: Liu, Huanxin, An, Zhihai, Liu, Xingquan, Wang, Xi, Liu, Zhen
Format: Article
Language:English
Subjects:
Axial stress
Boreholes
Crack initiation
Crack propagation
Deformation
Excavation
Failure modes
Fractures
Geology
Granite
Hydraulics
Mining
Mining engineering
Potassium
Propagation
Quartz
Strain burst
Stress state
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Summary:A series of true triaxial compression (TTC) tests was conducted on granite specimens to investigate their fracture behavior. The granite was sampled from a 1500‐m‐deep exploration borehole located on the Sanshandao gold field in Shandong Province, China, where a 1915‐m deep vertical shaft was planned. Under true triaxial stress, the fracture of the granite specimen shows anisotropic characteristics, which is manifested as different strains in the three directions of the specimen, and the macroscopic fractures formed are parallel to the direction of maximum principal stress σ 1 and intermediate principal stress σ 2 . In addition, the effects of the intermediate principal stress σ 2 and the minimum principal stress σ 3 on the fracture of granite specimen are different. A higher σ 2 causes the post‐peak curve of the granite specimen to develop toward a Class‐II type of curve, and the failure mode develops toward splitting failure, while a higher σ 3 causes the post‐peak curve of the granite specimen to develop toward a Class‐I type of curve, and the failure mode develops toward shear failure. In particular, under the stress regime whereby σ 3 = 0, σ 2 = 40 MPa, it simulates the tangential stress adjustment process when the shaft is excavated to a depth of 1000 m. The fracture mode of the granite specimen and the post‐peak curve characteristics both indicate that the shaft excavation to this depth has the risk of inducing a strain burst.
ISSN:1687-8086
1687-8094
DOI:10.1155/adce/7363711