Abstract Low-grade metamorphic rocks show limitations in relation to the evaluation of weathering effects on macroscopic characteristics of the rock matrix due to their fine texture. In addition, the anisotropic character and high weathering impose difficulties in the preparation of samples for laboratory tests commonly used in the acquisition of physical and mechanical parameters for geotechnical purposes. This paper presents the results of a study carried out on the characterization of weathering effects on the morphology of typical profiles and on textural and mineralogical characteristics and physical and mechanical properties of weathering products of phyllites under tropical climate. The authors selected three road cut slopes and different geological materials according to their weathered state. Samples were collected for microscopic description on petrographic thin sections, and to obtain index and mechanical properties, through point load test (PLT). Detailed descriptions were performed in the field and in situ strength was estimated with a Schmidt hammer. The results show that the geological structures had a strong influence in the weathering profile, controlling the morphology of studied profiles. Weathering process was not uniform in rocks when they reached a more advanced degree of degradation. However, physical parameters associated with mineralogy were useful in predicting and differentiation the stages of phyllite weathering.

中文翻译：

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巴西MG Quadrilátero Ferrífero地区热带气候下形成的千枚岩风化剖面特征

摘要 低品位变质岩质地细腻，在评价风化作用对岩石基质宏观特征的影响方面存在局限性。此外，各向异性特征和高风化性给通常用于获取岩土工程物理和机械参数的实验室测试样品的制备带来了困难。本文介绍了在热带气候下风化对典型剖面形态的影响以及对千枚岩风化产物的结构和矿物学特征以及物理和机械性能的表征的研究结果。作者根据风化状态选择了三个道路挖方坡和不同的地质材料。采集样品对岩相薄片进行显微描述，并通过点载荷试验（PLT）获得指标和力学性能。在现场进行了详细描述，并用施密特锤估计了原位强度。结果表明，地质构造对风化剖面有很强的影响，控制着研究剖面的形态。当岩石达到更高级的退化程度时，岩石的风化过程并不均匀。然而，与矿物学相关的物理参数可用于预测和区分千枚岩风化阶段。在现场进行了详细描述，并用施密特锤估计了原位强度。结果表明，地质构造对风化剖面有很强的影响，控制着研究剖面的形态。当岩石达到更高级的退化程度时，岩石的风化过程并不均匀。然而，与矿物学相关的物理参数可用于预测和区分千枚岩风化阶段。在现场进行了详细描述，并用施密特锤估计了原位强度。结果表明，地质构造对风化剖面有很强的影响，控制着研究剖面的形态。当岩石达到更高级的退化程度时，岩石的风化过程并不均匀。然而，与矿物学相关的物理参数可用于预测和区分千枚岩风化阶段。