Laboratory investigation on gas permeability of compacted GMZ bentonite under a coupled hydraulic-mechanical effect

Liu, Jiangfeng; Ni, Hong-Yang; Cao, Xu-Lou; Ma, Ling; Guo, Jingna; Chen, Xu

doi:10.1016/j.enggeo.2020.105761

Cited by 34 publications

(9 citation statements)

References 49 publications

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“…e GMZ specimen was prepared by compacting the treated powders in a rigid oedometer cell with an inner diameter of 50 mm. e dry density of the prepared specimen is 1.72 g/cm 3 , and the initial water content is 15.16%. e earlier studies [3,8] show that the compacted GMZ bentonite has low permeability due to its small pore size.…”

Section: Sample Preparationmentioning

confidence: 99%

“…Bentonite clay is often chosen as a buffer and backfill material between the waste canister and the host rock or as seals in excavated disposal galleries in geological disposal of highlevel radioactive waste. It exhibits a few favorite characteristics, such as high swelling, strong sorption ability, and low hydraulic conductivity [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…e swelling ability can reduce macroscopic porosity to limit microbial activity, reduce the hydraulic conductivity, prevent any further propagation of the excavation disturbed zone (EDZ) in the rock, and ensure that the buffer is self-sealing. erefore, understand the swelling process is critical in the evaluation of the long-term performance of a bentonite buffer [3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, the swelling and shrinkage of the Gao-Miao-Zi (GMZ) bentonite, considered as a possible material for engineered barriers in Chinese geological disposal [1,3,4,8], are studied. We present a new procedure to conduct drying and wetting tests combined with X-CT measurements.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation on Drying and Wetting of GMZ Bentonite Using X‐Ray Tomography and Volumetric Digital Image Correlation Technique

Chen

Yang

2020

Advances in Civil Engineering

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To investigate the shrinking and swelling properties of Gao-Miao-Zi (GMZ) bentonite, which has been considered as engineering barriers for high-level radioactive nuclear waste disposal in China, drying and wetting tests were carried out. The microstructure of the material at each hydric state was recorded using X-ray tomography (X-CT). The 3D images of the material were analyzed using digital volume correlation (DVC) technique, and the full-field strains at mesoscale (i.e., in the order of clay aggregate) during drying and wetting were quantified. The results show that the GMZ bentonite exhibits notable swelling characteristics during wetting and the swelling strain of the material is up to 8% at mesoscale. The full-field strain in 3D of the material is heterogeneous, anisotropic, and irreversible during drying and wetting. The corresponding deformation mechanisms are discussed. Two different swelling mechanisms were also identified: traction occurs in the interface between the matrix and inclusions during swelling; pre-existing fissure closes during swelling.

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Section: Sample Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation on Drying and Wetting of GMZ Bentonite Using X‐Ray Tomography and Volumetric Digital Image Correlation Technique

Chen

Yang

2020

Advances in Civil Engineering

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“…Currently, the most feasible way to isolate the HLW from the biosphere is to seal them in a geological disposal repository underground for 500-1000 m. Granite, characterized by low permeability and high strength, is a potential host rock for HLW. It is reported that Beishan granite is chosen as the host rock of a HLW repository in China [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study on Mechanical Properties and Deformation Behavior of Beishan Granite considering Heterogeneity

Wang

Tan

Li³

et al. 2021

Advances in Civil Engineering

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Disposal of high-level radioactive waste (HLW) deep underground is one of the most challenging research subjects in rock engineering. In China, Beishan granite is usually chosen as host rock for the construction of the HLW repository. In this study, mechanical tests are conducted on Beishan granite and the stress-strain state during the complete failure process is analyzed by numerical simulation. The results show that the tensile strength and uniaxial compressive strength of Beishan granite are 8.66 and 162.9 MPa, respectively. Dilatancy appears when the stress reaches about 81% of the peak strength. Heterogeneity is introduced by Weibull distribution in numerical simulation. With the increase of homogenization degree, the degraded elements are more easily to concentrate locally. Based on experimental and numerical simulation results, it is noticeable that the sample volume is basically in the state of compaction before reaching the peak strength. The elements are more likely to show expansion, and the splitting failure dominates the destroy mode when the confining pressure is relatively low. With increasing confining pressure, more and more degraded elements are concentrated in the shear band, which develops from the surface to the interior of the sample during loading. Therefore, the granite shows ductile mechanical response characteristics when the confining pressure is relatively high. The results are instructive for the construction of the repository.

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Experimental study of gas permeability evolution in tight sandstone with damage and cracking along various stress loading paths

Zha

Zhou

Liu

et al. 2021

Bull Eng Geol Environ

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Laboratory investigation on gas permeability of compacted GMZ bentonite under a coupled hydraulic-mechanical effect

Cited by 34 publications

References 49 publications

Experimental Investigation on Drying and Wetting of GMZ Bentonite Using X‐Ray Tomography and Volumetric Digital Image Correlation Technique

Experimental Investigation on Drying and Wetting of GMZ Bentonite Using X‐Ray Tomography and Volumetric Digital Image Correlation Technique

Experimental and Numerical Study on Mechanical Properties and Deformation Behavior of Beishan Granite considering Heterogeneity

Experimental study of gas permeability evolution in tight sandstone with damage and cracking along various stress loading paths

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