Swelling pressure characteristics of compacted Chinese Gaomiaozi bentonite GMZ01

Schanz, Tom; Al-Badran, Yasir M.

doi:10.1016/j.sandf.2014.06.026

Cited by 73 publications

(13 citation statements)

References 29 publications

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“…Saba et al [12] explained the anisotropic of the bentonite-sand mixture through microstructure images. Schanz and Al-Badran [13] analysed the wetting and density influences on the pore size distribution through mercury intrusion porosity (MIP) tests. Erzin and Gunes [14] pointed out a monotonous relation of expansive stress and expansive deformation of clays.…”

Section: Introductionmentioning

confidence: 99%

Factors Affecting the Swelling‐Compression Characteristics of Clays in Yichang, China

Huang

Wang

Zhou

et al. 2019

Advances in Civil Engineering

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Expansive soil has been studied for eighty decades because it is prone to cause geotechnical engineering accidents. The results of the moisture content effects on the expansive pressure were not consistent in the literatures. In this paper, swelling deformation and pressure tests were conducted to clarify the effects of the initial water content on the swelling properties. The relation of expansive stress and initial moisture content was accurately described with a Gaussian distribution, unlike in the previously published studies. These results could be explained by the change in the microstructure with diverse moisture contents. In addition, dry density and vertical stress influences on expansive properties were analysed. With an increase in the vertical loading, the soil samples first expanded, and then the samples with a lower dry density collapsed; however, the samples with a higher dry density did not collapse, even under a considerable vertical loading. Furthermore, the relation between stress path and expansive pressure was examined. It was observed that the swelling pressures obtained from the constant volume tests were greater than the results from the swell under load tests. The relationship between the swelling pressure and swelling strain was also analysed.

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Section: Introductionmentioning

confidence: 99%

Factors Affecting the Swelling‐Compression Characteristics of Clays in Yichang, China

Huang

Wang

Zhou

et al. 2019

Advances in Civil Engineering

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“…Hydration of bentonite samples under confined conditions has been usually reported to result in an increase in micropore void ratio and a homogenization of the pore sizes towards smaller values (e.g. [22]). This was the case of the bentonite samples retrieved from the FEBEX in situ test after 18 years of operation [27] and also of binary samples of blocks and pellets saturated in an oedometer [34].…”

Section: Discussionmentioning

confidence: 99%

Bentonite swelling into a void under suction or water flow

2022

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In the context of the deep geological disposal of nuclear waste and to improve the understanding of the homogenisation process of bentonite barriers, in particular with regard to the filling of technological voids, tests were performed with compacted FEBEX bentonite samples hydrated under limited axial swelling conditions. The samples were saturated from the top surface using the vapour transfer technique (imposing suctions of 6 and 0.5 MPa), or with deionised water injected at a low flow rate either from the bottom surface or from the gap on top. The final water content of the samples saturated via vapour transfer was related to the suction imposed during the tests according to the water retention curve. Thus, the final water content of the samples tested under suction 6 MPa was lower and not enough to allow sufficient bentonite swelling to close the gap. In contrast, the samples saturated under suction 0.5 MPa reached higher water contents and were able to fill the gap before the equilibrium water content had been reached. In the tests performed with liquid water supplied through the gap, the samples were able to swell easily into the open void and the gap closed earlier than when hydration took place from the opposite end. In all the tests, the final water content of the bentonite was higher and the dry density lower towards the hydration surface. These gradients were more remarkable and persistent as the initial strain was larger. No completely homogeneous density or water content distribution was observed in any of the tests. These changes were also reflected in the pore size distribution. The pores of size larger than the upper limit of mercury intrusion porosimetry (~ 550 µm) were also quantified, which allowed a better representation of the pore size distribution of the more swollen samples. Although the void ratio corresponding to pores smaller than 200 nm (em) was initially higher, over time the volume of macropores (eM) increased more, giving place to an overall decrease in the em/eM ratio, which tended to be constant along the samples in the longest tests. In the first stages of hydration, the macropore void ratio and size considerably increased close to the gap in the tests with saturation from it.

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“…The factors affecting the swelling of the bentonite can be classified into two categories, namely internal factors, including specific surface area, cation exchange capacity, properties of pore water (ion type and concentration), and external factors, such as DD, water content, and compaction method [42]. The maximum swelling pressure increases with increasing montmorillonite content and the initial DD.…”

Section: Swelling Characteristicsmentioning

confidence: 99%

Properties of Granulated Bentonite Mixtures for Radioactive Waste Disposal: A Review

Nazir¹

2021

GEOMATE

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Bentonite has long been considered as a potential sealing material in engineered barrier systems (EBS) for the geological disposal of radioactive waste due to its favorable physical and chemical properties. In some disposal concepts, the research evolution has led to the adaption of granulated bentonite mixtures (GBM) as a candidate buffer/backfill material owing to its high compaction properties, operational advantages, and ability to close gaps between the seal and host rock. A thorough understanding of the behavior of GBM is essential for proper design and construction of an efficient repository. As compared to compacted bentonite blocks, studies on GBM are somewhat limited. Thus, a review of former experimental studies conducted on GBM over the past two decades was performed. The topics included compaction properties, thermo-hydromechanical properties, gas transport, and microstructure. This work comprises a summary table listing material properties, sample scale, methodology, test conditions, and graphical representation of results. Based on the review, prospects for further investigations/studies have also been recommended to understand the behavior of GBM.

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Swelling pressure characteristics of compacted Chinese Gaomiaozi bentonite GMZ01

Cited by 73 publications

References 29 publications

Factors Affecting the Swelling‐Compression Characteristics of Clays in Yichang, China

Factors Affecting the Swelling‐Compression Characteristics of Clays in Yichang, China

Bentonite swelling into a void under suction or water flow

Properties of Granulated Bentonite Mixtures for Radioactive Waste Disposal: A Review

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