Alteração e alterabilidade de rochas básicas intrusivas metamorfizadas e filitos sericíticos da região do Quadrilátero Ferrífero e sua implicação no comportamento mecânico

• Autor(a) principal: Santiago, Luis Otávio Rigueira
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/810
• topic: Alteração; Alterabilidade; Intemperismo; Rocha metamórfica; Weathering; Weatherability; Igneous rocks; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::GEOTECTONICA

The present work presents the results of physical, mechanical and mineralogical study of two rock types commonly found at Quadrilátero Ferrífero region (Minas Gerais State, Brazil). The main purpose of the study was to characterize the weatherability of those rocks when exposed to weathering agents that may cause problems in some civil engineering works, mainly mining cut slopes as its mechanical properties vary significantly with the development of weathering in a short period of time, resulting in low strength materials. The study was carried on Class II rock samples of Pico do Itabirito and Tamanduá mines, collected in both rock drilling wells and rock slope faces, and in undisturbed weathered block samples from Pico do Itabirito, Tamanduá and Capitão do Mato mines. All samples were submitted to physical, mineralogical and mechanical tests. Class II rock samples were initially submitted to accelerated (natural, with ethylene glycol and water-oven) cycling tests in order to characterize both weatherability and mineralogical, mechanical and physical changes due to weathering. For more weathered samples with soil-like behavior characterization was based on tests such as Atterberg limits, grain size distribution, solid specific mass, consolidation tests, triaxial strength tests and mineralogical characterization through X-ray diffraction, petrography analysis and SEM images. Additionally, a method to propose a weathering scale was developed.