An Experimental Study of the Effects of Filling Degree on Shear Behavior and Acoustic Emission Characteristics of Kaolinite-Filled Granite Joints

The existence of kaolinite inside the granite joints reduces the direct contact between the jointed rock walls, which is an unfavorable factor for the stability of underground engineering. However, there are limited studies addressing kaolinite-filled granite joints of different filling degrees (the...

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Bibliographic Details
Published in:KSCE journal of civil engineering 2024, 28(7), , pp.2966-2981
Main Authors: Cao, Yangbing, Zhang, Yaoyao, Liu, Zhi, Bao, Min
Format: Article
Language:English
Subjects:
Acoustic emission
Civil Engineering
Deformation
Engineering
Exponential functions
Failure mechanisms
Geotechnical Engineering & Applied Earth Sciences
Granite
Industrial Pollution Prevention
Jointed rock
Kaolinite
Roughness coefficient
Shear properties
Shear strength
Shear stress
Shear tests
Shearing
Tunnel Engineering
토목공학
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Summary:The existence of kaolinite inside the granite joints reduces the direct contact between the jointed rock walls, which is an unfavorable factor for the stability of underground engineering. However, there are limited studies addressing kaolinite-filled granite joints of different filling degrees (the ratio of filling thickness t to the maximum fluctuation height a of the joint surface ( t / a )) even to this day, and the shear failure mechanisms of kaolinite-filled joints remain unclear. Direct shear tests of kaolinite-filled joints with different filling degrees are carried out in this study, and the acoustic emission (AE) activities during the shearing are real-timely monitored. The results show that the filling degree has a significant influence on the shear properties and AE characteristics of kaolinite-filled joints. With the increase of the filling degree, the shear stress drop is less significant, and the normal deformation gradually transitions from “first shear contraction and then shear dilation” to “shear contraction”, which is accompanied by the weakening of AE signals. The increase in filling degree allows a transition of the joint behavior from the asperity-dominated damage mode to the kaolinite-dominated shear sliding mode. Moreover, the filling degree is correlated with the joint roughness coefficient (JRC) in the form of an exponential function to modify Barton’s shear strength criterion. The present study gets insights into the shear failure mechanisms of kaolinite-filled joints with various filling degrees and helps interpret the field observations.
ISSN:1226-7988
1976-3808
DOI:10.1007/s12205-024-1085-5