EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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2 resultados
Resultados da Pesquisa
Item Bayesian inference of rock strength anisotropy : uncertainty analysis of the Hoek–Brown failure criterion.(2021) Gomes, Guilherme José Cunha; Gaona, John Harry Forero; Vargas Júnior, Eurípedes do Amaral; Vrugt, Jasper A.Strength properties of most sedimentary and metamorphic rocks are known to vary with direction. Knowledge of this so-called rock anisotropy is of utmost importance for reliability analysis and engineering design. The purpose of this paper is twofold. First, we propose a formulation of the Hoek–Brown (HB) failure criterion, which calculates strength anisotropy using a non-uniform scaling of the stress tensor. We use two scaling factors, CN and CS , to link the orientation of the anisotropy planes with the loading direction. As we assume isotropic parameters for intact rock, our HB model formulation is relatively easy to use and has the additional advantage that it does not demand any modifications to the HB failure criterion. Second, we embed our HB model formulation in a Bayesian framework and illustrate its power and usefulness using experimental data of anisotropic rock samples published in the literature. Results demonstrate that our HB model formulation predicts accurately measured peak strengths of rocks with different degrees of anisotropy, confining stresses and anisotropy orientations. The uncertainty in peak strength of anisotropic rocks can be quite large, reiterating the need for an explicit treatment of strength anisotropy uncertainty in rock mechanics studies. The Bayesian methodology is general-purpose, and, as such, can help better inform geotechnical engineers, contractors and other professionals about rock conditions and design reliability and assist decision makers in determining the overall risks of engineering structures.Item A cross-anisotropic elastoplastic model applied to sedimentary rocks.(2020) Gaona, John Harry Forero; Gomes, Guilherme José Cunha; Vargas Júnior, Eurípedes do Amaral; Falcão, Flávia de Oliveira Lima; Velloso, Raquel QuadrosStrength and deformability properties of sedimentary rocks are difficult to characterize as these geomaterials show anisotropic mechanical behavior, which cannot be adequately evaluated by an isotropic constitutive model. This essay proposes a cross-anisotropic elastoplastic model to evaluate stress–strain relationships of sedimentary rocks. The approach couples the twelve-parameter Lade–Kim isotropic model with a non-uniform scaling of the stress tensor and includes two scaling parameters that link the orientation of the bedding planes with the loading direction. The anisotropic model parameters can be conveniently determined using Bayesian analysis. We illustrate our method using triaxial tests on a variety of confining stresses and bedding plane orientations for a travertine and a Tournemire shale. Our results demonstrate that the predicted maximum deviatoric stresses and the simulated stress–strain curves are shown to be in good agreement with the measured data.