Alternativa de melhoramento de solos tropicais para uso em sistemas basais de selagem, através da aplicação de bentonita

AUTOR(ES)

Magali Kenya Farnezi

DATA DE PUBLICAÇÃO

2006

RESUMO

Among all the constructive elements in waste containment systems (e.g. sanitary and industrial landfills and waste ponds), liners and cover systems have been seen as the greatest concern. In Brazil, the use of compacted lateritic soil for this purpose is widely accepted, due to the great occurrence of this type of soil. At the same time, the proposal of using compacted mixtures of lateritic soil and bentonite for decreasing hydraulic conductivity seems to be attractive. Besides this parameter, the compatibility between the mixture and the leachate (waste liquid) must be addressed. However, few studies were found dealing at the same time with geotechnical and chemical aspects of these mixtures for liner systems. This dissertation presents a geotechnical and geochemical evaluation of two mixtures of a typical lateritic soils and bentonite for liner usage purpose. The proportions used were 3 and 6% (dry weight). Conventional geotechnical characterization was performed, along with mineralogical and physical-chemical characterization. The hydraulic conductivity was evaluated through rigid and flexible wall permeameters. The compatibility between the soil and different chemical solutions was also assessed. The characterization results showed that, as opposed to what was expected, the clay content of the mixtures decreased when related to the natural soil sample. On the other hand, the plasticity greatly increased in the mixture samples. In terms of hydraulic conductivity, only the mixture with 6% of bentonite showed some significant decreasing in this parameter. The results also demonstrated that the bentonite addition improved the compatibility between the compacted mixtures and the chemical solutions tested. Finally, the mixture 6% (dry weight) is suggested for reducing the K parameter of this lateritic soil.

ASSUNTO(S)

liner system, cover system, lateritic soils, bentonite, compatibility, hydraulic conductivity. saneamento ambiental sistemas selantes, solos lateríticos, bentonita, compatibilidade, condutividade hidráulica

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