Weathering zones on metamorphic rocks from Rio de Janeiro-Physical, mineralogical and geomechanical characterization

This work presents and analyzes results obtained on a research program aiming at the characterization of materials belonging to weathering profiles developed in the three most common metamorphic rocks occurring in Rio de Janeiro, Brazil-Leptinite, Kinzigite and Augen Gneiss. Initially, a comprehensive field description is presented in order to point out the main weathering patterns observed for these rocks. Samples from different weathering levels were identified and tested in order to determine their mineralogical, physical and geomechanical properties. The obtained results are discussed and an evaluation of the influence of weathering on rock properties is presented. Correlations between the physical and mechanical properties of the tested materials are also presented. (C) 2009 Elsevier B.V. All rights reserved.