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An Empirical Study on Water-Induced Shear Weakening Behaviors of Rough-Walled Sandstone Joints
https://orcid.org/0000-0003-3280-206X
Abstract The presence of water in sandstone joints affects the shear characteristics of the joints, which is of considerable importance to the stability evaluations of rock slopes or tunnels subjected to water fluctuations. A series of direct shear tests with three immersion durations (30, 180, and 360 d) in water were conducted on the sandstone joint specimens collected from the reservoir area of the Three Gorges hydropower station, China. To perform duplicate tests, three-dimensional (3D) optical scanning and 3D rigid engraving were coupled to produce sandstone joints with the same surface morphology. The shear curves of the dry and immersed sandstone joints were divided into the three stages of sliding, shear-breaking, and post-peak wearing. The damaged area of the immersed joints decreased with the increased immersion duration under the same normal loading. The immersion duration did not affect the shear mode of the joints, and the peak and residual shear strengths of the sandstone joints decreased by approximately 10–28% and 2.9–26.4%, respectively, after the 360-d immersion. Experimental results pointed to the lubricant effect as the dominant mechanism for a water-induced reduction in the shear strength of the joints, followed by the chemical dissolution effect. Given the lubricant and chemical dissolution effects, a semi-empirical shear strength criterion was proposed to predict the peak shear strength of the rock joints subjected to the immersion durations. Validation against experimental shear data obtained in this study and from related literature indicated satisfactory accuracy of the proposed criterion for predicting the peak shear strength after the immersion. An engineering example of the Jianchuandong unstable rock mass located in the Three Gorges reservoir was used to demonstrate the function of wetting in lowering its safety factor.
Highlights 3D scanning and 3D engraving were coupled to produce sandstone joints.Direct shear tests with different immersion durations were conducted on joints. A novel shear strength criterion was developed considering immersion duration.
An Empirical Study on Water-Induced Shear Weakening Behaviors of Rough-Walled Sandstone Joints
https://orcid.org/0000-0003-3280-206X
Abstract The presence of water in sandstone joints affects the shear characteristics of the joints, which is of considerable importance to the stability evaluations of rock slopes or tunnels subjected to water fluctuations. A series of direct shear tests with three immersion durations (30, 180, and 360 d) in water were conducted on the sandstone joint specimens collected from the reservoir area of the Three Gorges hydropower station, China. To perform duplicate tests, three-dimensional (3D) optical scanning and 3D rigid engraving were coupled to produce sandstone joints with the same surface morphology. The shear curves of the dry and immersed sandstone joints were divided into the three stages of sliding, shear-breaking, and post-peak wearing. The damaged area of the immersed joints decreased with the increased immersion duration under the same normal loading. The immersion duration did not affect the shear mode of the joints, and the peak and residual shear strengths of the sandstone joints decreased by approximately 10–28% and 2.9–26.4%, respectively, after the 360-d immersion. Experimental results pointed to the lubricant effect as the dominant mechanism for a water-induced reduction in the shear strength of the joints, followed by the chemical dissolution effect. Given the lubricant and chemical dissolution effects, a semi-empirical shear strength criterion was proposed to predict the peak shear strength of the rock joints subjected to the immersion durations. Validation against experimental shear data obtained in this study and from related literature indicated satisfactory accuracy of the proposed criterion for predicting the peak shear strength after the immersion. An engineering example of the Jianchuandong unstable rock mass located in the Three Gorges reservoir was used to demonstrate the function of wetting in lowering its safety factor.
Highlights 3D scanning and 3D engraving were coupled to produce sandstone joints.Direct shear tests with different immersion durations were conducted on joints. A novel shear strength criterion was developed considering immersion duration.
An Empirical Study on Water-Induced Shear Weakening Behaviors of Rough-Walled Sandstone Joints
https://orcid.org/0000-0003-3280-206X
Abstract The presence of water in sandstone joints affects the shear characteristics of the joints, which is of considerable importance to the stability evaluations of rock slopes or tunnels subjected to water fluctuations. A series of direct shear tests with three immersion durations (30, 180, and 360 d) in water were conducted on the sandstone joint specimens collected from the reservoir area of the Three Gorges hydropower station, China. To perform duplicate tests, three-dimensional (3D) optical scanning and 3D rigid engraving were coupled to produce sandstone joints with the same surface morphology. The shear curves of the dry and immersed sandstone joints were divided into the three stages of sliding, shear-breaking, and post-peak wearing. The damaged area of the immersed joints decreased with the increased immersion duration under the same normal loading. The immersion duration did not affect the shear mode of the joints, and the peak and residual shear strengths of the sandstone joints decreased by approximately 10–28% and 2.9–26.4%, respectively, after the 360-d immersion. Experimental results pointed to the lubricant effect as the dominant mechanism for a water-induced reduction in the shear strength of the joints, followed by the chemical dissolution effect. Given the lubricant and chemical dissolution effects, a semi-empirical shear strength criterion was proposed to predict the peak shear strength of the rock joints subjected to the immersion durations. Validation against experimental shear data obtained in this study and from related literature indicated satisfactory accuracy of the proposed criterion for predicting the peak shear strength after the immersion. An engineering example of the Jianchuandong unstable rock mass located in the Three Gorges reservoir was used to demonstrate the function of wetting in lowering its safety factor.
Highlights 3D scanning and 3D engraving were coupled to produce sandstone joints.Direct shear tests with different immersion durations were conducted on joints. A novel shear strength criterion was developed considering immersion duration.
An Empirical Study on Water-Induced Shear Weakening Behaviors of Rough-Walled Sandstone Joints
Zhang, Guohua (author) / Zhang, Bowen (author) / Zou, Junpeng (author) / Xiong, Feng (author) / Lin, Zhiping (author) / Zhang, Zhanrong (author)
2023
Article (Journal)
Electronic Resource
English
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB41
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| British Library Online Contents | 2017
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