An alternative approach for the use of DDL theory to estimate the swelling pressure of bentonites

Schanz, Tom; Khan, Muhammad Ibrar; Al-Badran, Yasir M.

doi:10.1016/j.clay.2013.07.018

Cited by 19 publications

(7 citation statements)

References 26 publications

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“…Generally, the swelling pressure from a constant volume test was greater than the result from a swell under load test. A monotonous relation between the swelling pressure and swelling strain was achieved, as expressed by equation (4). is equation could be used to calculate the one parameter, if the other parameter was known.…”

Section: Resultsmentioning

confidence: 99%

“…Bharat et al [3] provided a new method to evaluate the swelling pressure using the diffuse double layer theory. Schanz et al [4] figured out the swelling pressure for different dry densities by new equations on the basis of diffuse double layer theory. e suction effect on expansive properties has been analysed (Wray et al [5]; Adem and Vanapalli [6]; and Lin and Cerato [7]).…”

Section: Introductionmentioning

confidence: 99%

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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: Resultsmentioning

confidence: 99%

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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“…Müller-Vonmoos and Kahr, 1982;Herbert and Moog, 2002;Tripathy et al, 2004;Schanz and Tripathy, 2009;Schanz et al, 2013;Wang et al, 2013). Regarding the China GMZ01, Xie et al (2006) carried out 12 constant volume tests to measure the swelling pressure.…”

Section: Measurement Of Swelling Pressurementioning

confidence: 98%

Swelling pressure characteristics of compacted Chinese Gaomiaozi bentonite GMZ01

Schanz

Al-Badran

2014

Soils and Foundations

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Gaomiaozi bentonite (GMZ01) has been decided upon as the first option for use as buffer/backfill materials in the deep disposal of high-level radioactive waste in China. The basic functions of the materials used in the waste repositories request among others a sufficient swelling pressure and low hydraulic conductivity in order to provide long-term stability to the barrier system under environmental pressure and behavior of the waste loads. As such, it is necessary to investigate the influence of initial dry density on the swelling properties of Gaomiaozi bentonite (GMZ01) in order to achieve better design of buffer/backfill materials. In this study the swelling pressure of GMZ01 has been studied and analyzed by multi and one-step wetting constant volume tests with five different dry densities (1.15, 1.35, 1.50, 1.60 and 1.75 mg/m 3 ). Results show that swelling pressure changes with time nonlinearly, while there is a linear relationship between time/swelling pressure and time. Curves of swelling pressure and the amount of absorbed water varying with time can be classified into typical phases. For the GMZ01 tested here, the initial dry density is an important factor influencing the swelling pressure. The results show that there is an exponential relationship between swelling pressure and dry density. Moreover, comparison was done between the experimental swelling pressure results of used GMZ bentonite in this study and other bentonites cited in literature: (i) other GMZ's and (ii) different types of bentonites proposed as buffer/backfill materials (i.e., MX80, Kunigel, Montigel, and Calcigel). The effect on the microstructure of the density and the wetting under the constant volume condition (after the swelling pressure test) has been investigated by studying the results of pore size distribution for GMZ01 by using the mercury intrusion porosimetry (MIP) test and the environmental scanning electron microscope (ESEM) photos. Finally, two different theoretical concepts were used to estimate the swelling pressure (the modified DDL and thermodynamics approaches). The results of the two methods show that the swelling pressure results compare relatively well with the experimental data for the GMZ bentonite.

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“…System geochemistry can also affect stresses within a D r a f t soil acting normal to the shear plane. Forces can be generated as a result of volume changes during formation of new minerals or mineral dissolution, or with existing mineralogy by processes such as clay hydration and cation substitution leading to swelling (Tuller and Or 2003;Tripathy et al 2004;Schantz et al 2013. Net repulsive (R) and net attractive (A) long-range forces are generated between soil particles and their diffuse double layers (e.g.…”

Section: Residual Strength and Geochemistrymentioning

confidence: 99%

“…Net repulsive (R) and net attractive (A) long-range forces are generated between soil particles and their diffuse double layers (e.g. : Lambe 1960, Barbour 1990; Barbour and Yang 1993;Tripathy et al 2004;Schantz et al 2013). The attractive forces (A) are primarily controlled by van der Waals forces, which are dependent upon the temperature and dielectric permittivity of the intervening inter-particular space.…”

Section: Residual Strength and Geochemistrymentioning

confidence: 99%

Effects of oxidation on residual shear strength of shales within Lea Park Formation

Nichol

Froese²,

Sharma

et al. 2016

Can. Geotech. J.

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The residual shear strength of Cretaceous Lea Park Formation shale near Lloydminster, Saskatchewan, was evaluated to determine its suitability for road construction. Exposure of these shales results in oxidation, leaching, and other geochemical changes, which may affect the physicochemical forces that control the shear strength behaviour. A laboratory geotechnical testing program was complemented with geochemical testing and modelling. In situ pore-water chemistry and cation-exchange site composition were determined from soil-water extracts using an equilibrium geochemical model. It was found that leaching by low ionic strength recharge removes dissolved and adsorbed sodium from surficial deposits. Sulfur oxidation overprinted the effects of leaching by releasing acidity and sulfate, increasing stored gypsum, and increasing dissolved and adsorbed magnesium. Shear testing indicated higher apparent residual friction angles for surficial samples with lower exchangeable sodium; however, this relationship is obfuscated by the impact of increased sand contents on increased strength. Samples at depth exhibited lower apparent residual friction angles with higher clay fractions and greater exchangeable sodium. Fully assessing the long-term stability of the material would require further laboratory testing, and a theoretical basis to link the geochemical model results to the calculation of physicochemical forces in multi-ion, multi-mineral systems. Qualitatively, it can be concluded that near-surface oxidized and leached shales have greater shear strength, with less risk of this strength changing as a result of post-construction weathering.

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An alternative approach for the use of DDL theory to estimate the swelling pressure of bentonites

Cited by 19 publications

References 26 publications

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

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

Swelling pressure characteristics of compacted Chinese Gaomiaozi bentonite GMZ01

Effects of oxidation on residual shear strength of shales within Lea Park Formation

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