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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Resultados da Pesquisa
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.Item Application of the discrete element method for modeling of rock crack propagation and coalescence in the step-path failure mechanism.(2013) Camones, Luis Arnaldo Mejía; Vargas Júnior, Eurípedes do Amaral; Figueiredo, Rodrigo Peluci de; Velloso, Raquel QuadrosThe present study evaluates the discrete element method (DEM) as a tool for understanding the step-path failure mechanism in fractured rock masses. Initially, the study simulates crack propagation and coalescence in biaxial and triaxial laboratory tests. The results of this analysis showthat the DEMaccurately represents these processes in comparison to other studies in the technical literature. The crack propagation and coalescence processes are important in the step-path failure mechanism for slopes. Simple examples of this mechanism were modeled, and their results were compared with those of the analytical model proposed by Jennings (1970). Among the possibilities suggested by Jennings,modelingwith DEMdid not provide a good approximation for the case of coplanar cracks, forwhich failures in the intact rock bridges should only be caused by shear forces. Inmodelingwith DEM, tensile failures occur within the sliding block, generating forces that are not considered in the Jennings model. The non-coplanar crack condition provided a better approximation, since the Jennings model formulation for this case includes the tensile failure of the rock. The main advantage of the DEM over other computational tools is its micromechanical representation of discontinuous media, which permits a better understanding of the step-path failure mechanism. However, good calibration of the macroscopic parameters of the rock and its discontinuities is necessary to obtain good results.