Consolidation Properties of Soil/Modified Bentonite Backfill in Salt Solution

Fang, Aiguo; Yang, Yuling; Yang, Zhongjun; Hua, Sudong; Wang, Jinchao; Zhou, Feng

doi:10.3390/w14121967

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…Previous studies have shown that the swelling performance of bentonite decreases with increasing ionic concentration in the pore solution 4,5 . For example, Ernesto 6 , Herber 7 , and Zhao 8 found that the swelling performance of FEBEX, MX-80, and GMZ bentonites decreases with higher concentrations of monovalent metal ions like K + and Na + .…”

Section: Introductionmentioning

confidence: 94%

Experimental Study on the Swelling Performance of Gaomiaozi Bentonite Buffer Material under Fe(II) Reducing Environment

Ming,

Dongke,

Jingli

et al. 2024

Preprint

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The release of Fe(II) from iron-based disposal canisters during the operational period of high-level radioactive waste (HLW) repositories may affect the swelling behavior of the buffer barrier, consequently impacting repository safety and stability. In this study, we employed a self-made dilatometer to measure the swelling characteristics of GMZ24 bentonite under varying Fe(II) concentrations. Our test results indicate that with increasing Fe(II) concentration, the time required for GMZ24 bentonite to swell decreases, while the final swelling pressure and swelling ratio exhibit an exponential decline. Through hydrochemical detection and mineralogical analysis, it is found that the decrease of swelling performance of bentonite is mainly due to the cation exchange between Na+ and Fe(II) in bentonite and the isomorphic replacement of Montmorillonite crystal and Fe(II) to generate chlorite. Finally, based on the double electrical layer theory, we derived a functional relationship describing the variation in swelling pressure and swelling ratio of GMZ24 bentonite as a function of Fe(II) concentration. This study provides a scientific basis for predicting and controlling the swelling behavior of buffer backfill materials in HLW repositories.

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Section: Introductionmentioning

confidence: 94%

Experimental Study on the Swelling Performance of Gaomiaozi Bentonite Buffer Material under Fe(II) Reducing Environment

Ming,

Dongke,

Jingli

et al. 2024

Preprint

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“…Another advantage of salt waste is its ability to crystallise and harden at the moment of moisture release. Salts belong to self-hardening materials [67]. Therefore, the introduction of additional components (binders/additives) or the use of another type of impact on the waste is the activation of the strength-gaining process.…”

Section: Backfill Componentsmentioning

confidence: 99%

“…The hardening process proceeds slowly as moisture evaporates. A saturated salt solution is used as a grouting fluid since the aggregate dissolves in water [67,68].…”

Section: Backfill Componentsmentioning

confidence: 99%

Principles of Sustainable Development of Georesources as a Way to Reduce Urban Vulnerability

Kongar-Syuryun,

Klyuev,

Golik

et al. 2024

Urban Science

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Humanity development is associated with higher spiritual and social behaviour and financial shape, which is an undeniable factor of urbanisation. Previously, in areas of georesource concentration, cities and settlements were formed with people exploiting these georesources. However, imperfect technologies lead to rapid depletion of reserves and industrial and environmental disasters, which affect the vulnerability of cities and the people living in them. The analysis of applied technologies has demonstrated that potash extraction is accompanied by a low recovery ratio, high mine accidents, and environmental problems. The principles of sustainable development of geo-resources for the creation of mining technologies that ensure industrial safety, environmental sustainability, and extending the life of the mining enterprise to save working places will reduce the vulnerability of cities. This article proposes the use of the room-and-pillar mining method with the replacement of natural supports with artificial ones. Three-stage stoping with backfill is considered. Numerical modelling has shown stabilisation of mining and geomechanical processes, which confirms the prospectivity of the method with backfill. For these purposes, this research presents a new backfill composition based on local industrial waste. Schemes of backfill preparation and feeding into the mined-out space are proposed. The proposed technology, based on the principles of sustainable development of georesources, is the foundation for an economically profitable, environmentally friendly, and socially responsible mining enterprise. The implementation of the principles of sustainable development of georesources will allow for the preservation of cities and reduce their vulnerability.

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“…For properties on the transport of pollutants for the GCL, the diffusion coefficient (Dd) was 3 × 10 −10 m 2 /s [30]. The retardation factor (Rd) for linear adsorption was chosen as 15 [31]. Other related parameters are summarized in Table 3.…”

Section: Parametersmentioning

confidence: 99%

“…It could be seen that the breakthrough was made at the shallow 0.9 m depth in the overlapping area where the amount of concentration was more than 10% of the source concentration [32], with consideration that the depth of the groundwater table For properties on the transport of pollutants for the GCL, the diffusion coefficient (D d ) was 3 × 10 −10 m 2 /s [30]. The retardation factor (R d ) for linear adsorption was chosen as 15 [31]. Other related parameters are summarized in Table 3.…”

Section: Parametersmentioning

confidence: 99%

Performances of the Soil–Bentonite Cutoff Wall Composited with Geosynthetic Clay Liners: Large-Scale Model Tests and Numerical Simulations

Zhan

Cao

Zhao³

et al. 2023

Sustainability

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The geosynthetic clay liner (GCL) overlap plays a key role in maintaining hydraulic performance of the barrier systems, e.g., the bottom liner and cover systems. However, its influences on the behavior of the vertical barrier have been rarely investigated. This paper aims to address this issue using the large-scale model test and 3-dimensional finite element (FE) modeling. In the model test, the GCL overlap at the width of 500 mm was tested under a constant hydraulic head of 1 m and confining stress ranging from 10 to 150 kPa using a newly developed large-scale apparatus. Compared with the flexible wall permeameter, this apparatus could guarantee full field-scale GCL overlap to be tested. Results showed that the effective hydraulic conductivity of the GCL overlap decreased from 10−8 to 10−9 cm/s as the confining stress increased from 10 to 150 kPa. The addition of supplemental bentonite paste in between the overlap with a water-to-bentonite ratio of 19:1 contributed to reducing the effective hydraulic conductivity by 60% compared with that for a GCL overlap without bentonite paste. The breakthrough time for the soil-bentonite (SB) cutoff wall composited with GCLs was 64% longer in comparison with that for the single SB wall. Additionally, the breakthrough after 50 years is made for the entire depth of the single SB wall while at the depth no more than 0.9 m for the composite wall with bentonite paste at the GCL overlap. With consideration that the depth of the groundwater table is generally greater than 1 m, the GCL–SB composite cutoff wall will exhibit a good performance in containing groundwater contaminants in the field, especially when applying bentonite paste at the GCL overlap.

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Consolidation Properties of Soil/Modified Bentonite Backfill in Salt Solution

Cited by 6 publications

References 30 publications

Experimental Study on the Swelling Performance of Gaomiaozi Bentonite Buffer Material under Fe(II) Reducing Environment

Experimental Study on the Swelling Performance of Gaomiaozi Bentonite Buffer Material under Fe(II) Reducing Environment

Principles of Sustainable Development of Georesources as a Way to Reduce Urban Vulnerability

Performances of the Soil–Bentonite Cutoff Wall Composited with Geosynthetic Clay Liners: Large-Scale Model Tests and Numerical Simulations

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