DEMIN - Departamento de Engenharia de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/510
Navegar
4 resultados
Resultados da Pesquisa
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.Item Numerical modeling of failure mechanisms in phyllite mine slopes in Brazil.(2014) Lana, Milene SabinoThis paper presents three case studies comprising failure mechanisms in phyllite mine slopes at Quadrilátero Ferrífero, State of Minas Gerais, Brazil. Numerical modeling techniques were used in this study. Failure mechanisms involving discontinuities sub parallel to the main foliation are very common in these mines. Besides, failure through the rock material has also been observed due to the low strength of phyllitesin this site. Results of this work permitted to establish unknown geotechnical parameters which have significant influence in failure processes, like the in situ stress field and the discontinuity stiffness.Item Influência da durabilidade no comportamento geotécnico dos filitos da Mina Pau Branco.(2012) Silva, Carolina Helena Caldeira; Lana, Milene SabinoPropõe-se, nesse trabalho, o estudo da influência da durabilidade no comportamento geotécnico das rochas do Talude Oeste da Mina Pau Branco, de propriedade da Vallourec & Mannesman (V&M) Mineração, localizada na serra da Moeda, no município de Brumadinho, Minas Gerais. No local, a ocorrência de fraturamento acentuado e de dobramentos, aliados ao clima regional, levou à formação de rochas com baixa resistência e elevados graus de alteração, fato que favorece mecanismos de instabilização. Foi avaliada a influência da durabilidade nas propriedades físicas dos filitos com graus distintos de alteração e resistência, através da realização de ensaios de durabilidade. Buscou-se, também, a partir do referido ensaio, identificar a existência de correlação entre a durabilidade e o modo de ruptura nos taludes em filitos, verificando, assim, se o referido índice pode ser utilizado como um indicador expedito do tipo de mecanismo de ruptura e da resistência do material. Os estudos incluíram, ainda, análises cinemáticas, para identificar condições para ocorrência de rupturas, segundo descontinuidades existentes no talude, e comparar tal ocorrência a rupturas observadas em campo. Para tal foi utilizado o software Dips5.0, da Rocsciense, Canadá.Item The use of inclined hemisphere projections for analyzing failure mechanisms in discontinuous rocks.(2003) Lana, Milene Sabino; Gripp, Maria de Fátima AndradeThis paper demonstrates the advantages of using inclined stereographic projections in kinematic analysis of rock blocks in discontinuous rock masses. Some examples of limiting cases are presented. The application of inclined projections is illustrated by its use in a mine slope in Brazil. It is clear from the discussion of these examples that inclined hemisphere projections provide better results than horizontal projections. It is also demonstrated that horizontal projections can lead to incorrect results in limiting cases.