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| Sultan, Nabil; Cui, Y. -j.; Delage, P.. |
| An underground research laboratory (URL) has been excavated in a deposit of Boom clay at a depth of 223 m by the SCK-CEN Belgian organisation near the city of Mol. This URL is devoted to research into nuclear waste disposal. This paper presents the results of an investigation carried out in the triaxial apparatus on specimens that were trimmed from blocks extracted during excavation sequences in the URL. In order to characterise the mechanical behaviour of the natural Boom clay and to examine the effect of initial and induced anisotropy on its constitutive behaviour, two series of triaxial tests were carried out. Special attention was devoted to the yield behaviour and the effects of stress history. Experimental results showed a clear relation between the... |
| Tipo: Text |
Palavras-chave: Anisotropy; Clays; Constitutive relations; Elasticity; Laboratory tests; Plasticity; Shear strength. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12414/9530.pdf |
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| Cunha,Jailson Cavalcante; Ruiz,Hugo Alberto; Freire,Maria Betânia Galvão dos Santos; Alvarez V.,Víctor Hugo; Fernandes,Raphael Bragança Alves. |
| The electrical charges in soil particles are divided into structural or permanent charges and variable charges. Permanent charges develop on the soil particle surface by isomorphic substitution. Variable charges arise from dissociation and association of protons (H+), protonation or deprotonation, and specific adsorption of cations and anions. The aim of this study was to quantify the permanent charges and variable charges of Reference Soils of the State of Pernambuco, Brazil. To do so, 24 subsurface profiles from different regions (nine in the Zona da Mata, eight in the Agreste, and seven in the Sertão) were sampled, representing approximately 80 % of the total area of the state. Measurements were performed using cesium chloride solution. Determination... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Clays; Cation exchange capacity; Structural charges; PH dependent charges. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000400012 |
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| Cruz,Lútecia Hiera da; Santana,Henrique de; Zaia,Cássia Thaïs Bussamra Vieira; Zaia,Dimas Augusto Morozin. |
| This work showed that the adsorption of glyphosate (GPS) depends on surface area for clays and amount of clays and CEC for soils. Organic matter (OM) had a secondary role in the adsorption of GPS on soils. The adsorption of GPS on soils from Londrina and Floraí counties and clays (montmorillonite, kaolinite) decreased when pH increased, however, for bentonite clay and soil from Tibagi county was kept constant. For the soils, the competitive adsorption between GPS and phosphate showed that displace of GPS by phosphate was related to the amount of clays, CEC and pH. GPS was not easily displaced by phosphate on the clays. The FT-IR spectra of the soils and clays showed that soil from Londrina resembled kaolinite. Thus, this could explain the results of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glyphosate; Adsorption; Clays; Soils. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132007000300004 |
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