Made available in DSpace on 2015-03-26T13:28:28Z (GMT). No. of bitstreams: 1 texto completo.pdf: 9684635 bytes, checksum: 3491aec02ba187b7f125d21090d312b3 (MD5) Previous issue date: 2013-08-01 / This paper presents a slope stability and groundwater flow analysis of rock masses of Alegria Centro and Alegria Sul pits, Samarco Mineração S.A., located in the Iron Quadrangle region, Minas Gerais State, Brazil. The main purpose was to characterize the mechanical properties - throughout GSI and RMR geomechanics classification methods, and hydrogeological characterization, of all rock and soil masses in the studied area, in order to produce data to support the preparation of a suitable pit design covering local particularities. This study included geological-geotechnical mapping, geotechnical drillhole logging, sampling of 45 undisturbed highly weathered block samples (classes V and VI) and drillhole core sampling. Physical and strength tests performed comprised geotechnical characterization tests, direct shear tests, uniaxial and triaxial strength tests and point load tests. To characterize the hydrogeological properties, in addition to the monitoring of groundwater level, field and laboratory experiments were carried out to determine the hydraulic conductivity and frequency fractures analyzes through the Cubic Law relation. In this study slope stability analyzes were performed by limit equilibrium and analyzes of flows by the finite element method, using the software SLIDE Rocscience Inc., with the determination of the critical safety factors before and after the drawdown. / Este trabalho apresenta uma avaliação da estabilidade e do fluxo subterrâneo dos maciços das cavas de expansão da Samarco Mineração S.A., denominadas Alegria Centro e Sul, localizadas na região do Quadrilátero Ferrífero, Minas Gerais, Brasil. O principal objetivo foi realizar uma caracterização das propriedades mecânicas para as quais combinaram-se os métodos de classificação geomecânica RMR e GSI, e hidrogeológicas, dos maciços rochosos e solos existentes na área de estudo, de maneira a produzir dados que permitissem a elaboração de um projeto de cava adequado à essas características. Este estudo contou com mapeamento geológico-geotécnico, descrição geotécnica de testemunhos de sondagens rotativas, amostragem de 45 blocos indeformados de rochas de alto grau de alteração (classes V e VI) e amostragem de testemunhos de furos de sondagens. Para caracterização das propriedades de resistência foram realizados ensaios de caracterização física, ensaios de cisalhamento direto, ensaios de compressão uniaxial e triaxial e ensaios de resistência à compressão puntiforme. Para caracterização das propriedades hidrogeológicas, além do monitoramento do nível d água subterrânea, foram conduzidos ensaios para determinação da condutividade hidráulica em campo, em laboratório e análises de frequência de fraturas através da relação conhecida como Lei Cúbica. No presente estudo foram realizadas análises de estabilidades por equilíbrio limite e análises de fluxos pelo método de elementos finitos, utilizando o software SLIDE da Rocscience Inc., com a determinação dos fatores de segurança críticos antes e após o rebaixamento do nível d água.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico

Made available in DSpace on 2014-07-29T15:03:33Z (GMT). No. of bitstreams: 1 Dissertacao Patricia Maria de Carvalho Soares.pdf: 3565512 bytes, checksum: b063397a71947658317311f45760e7a4 (MD5) Previous issue date: 2010-08-24 / The main objective is to develop, implement and evaluate a method to search for surfaces in order to determine the three-dimensional critical surface, corresponding to the lowest factor of safety of the embankment. They are also objectives of this study to evaluate the influence of the strength and elastic parameters the geometry of the slope safety factor and the 3D shape and position of the failure surface, as well as to evaluate the relationship between 2D and 3D safety factors. It was implemented an optimization routine in FORTRAN that performs the search for critical failure surface, whose safety factor is calculated by SAFE-3D program. The SAFE-3D program uses voltages coming from an elastic stress analysis performed by FlexPDE program, which uses the finite element method and provides the shear and normal stresses acting on the slope necessary to calculate the safety factor. For the analysis has been adopted as the ellipsoid shape of the rupture surface. The search method implemented examines safety factors obtained for a finite set of solutions and design variables as the coordinates of the center of the ellipsoid and the size of its three semi-axes. The search algorithm is implemented in successive tests of the factor of safety by SAFE-3D program, varying the position and dimensions of the ellipsoid for the determination of lower safety factor of slope. It was analyzed two examples of slopes, a symmetrical slope which varied the parameters of soil strength and the angle of the slope face and the other was the historic case of slipping Lodalen. The methodology implemented was successful in finding the critical failure surface, achieving consistency in results. The Poisson's ratio was very influential in the results of the safety factors of three-dimensional critical surfaces. It was also observed that there is less difference between the safety factors when keeping the shear stress unacceptable when these tensions are eliminated there is a closeness among the factors of safety. / O principal objetivo deste trabalho é desenvolver, implementar e avaliar um método de busca de superfícies de ruptura tridimensionais a fim de determinar a superfície crítica, correspondente ao menor fator de segurança do talude. São também objetivos deste trabalho avaliar a influência dos parâmetros de resistência e elásticos e da geometria do talude no fator de segurança 3D e no formato e na posição da superfície de ruptura, assim como avaliar a relação entre os fatores de segurança bi e tridimensionais. Foi implementada uma rotina de otimização na linguagem FORTRAN que realiza a busca pela superfície de ruptura crítica, cujo fator de segurança é calculado pelo programa SAFE-3D. O programa SAFE-3D utiliza tensões vindas de uma análise elástica de tensões realizada pelo programa FlexPDE, o qual utiliza o método dos elementos finitos e fornece as tensões normais e cisalhantes atuantes no talude necessárias para o cálculo do fator de segurança. Para a análise foi adotado o elipsóide como forma da superfície de ruptura. O método de busca implementado analisa fatores de segurança obtidos para um conjunto finito de soluções tendo como variáveis de projeto as coordenadas do centro do elipsóide e as dimensões dos seus três semi-eixos. O algoritmo de busca implementado consiste em análises sucessivas do fator de segurança através do programa SAFE-3D, variando-se a posição e as dimensões do elipsóide para a determinação do menor fator de segurança do talude. Foram analisados dois exemplos de taludes, um talude simétrico onde foram variados os parâmetros de resistência do solo e o ângulo da face do talude e o outro foi o caso histórico do escorregamento de Lodalen. A metodologia implementada teve êxito na busca pela superfície de ruptura crítica, conseguindo coerência nos resultados encontrados. O coeficiente de Poisson se mostrou muito influente nos resultados dos fatores de segurança tridimensionais de superfícies críticas. Foi observado também que existe uma menor diferença entre os fatores de segurança quando se mantêm as tensões cisalhantes inadmissíveis, quando estas tensões são eliminadas existe uma maior proximidade entre os fatores de segurança.

Este documento presenta la base metodológica para determinar la Estabilidad de taludes, en una de las carreteras de penetración con mayor crecimiento de tránsito vehicular; por ello su importancia en la construcción de una vía asfaltada para conectar los pueblos de esta parte norte del Perú. Asimismo, exponemos los diferentes procesos de desprendimientos o movimientos de masa que ocurren en los taludes; además de los factores que influencian el análisis de Estabilidad de Taludes, pasando a los Métodos de Diseño para la verificación de la condición de estabilidad y los posibles Métodos de Estabilización. Finalmente, se realizará un análisis de Estabilidad de Talud al Sector del Km. 17+200 al Km. 18+600 del Proyecto a través del Método seleccionado; hemos considerado como base los parámetros y características: morfológicas, litológicas, climatológicas, del suelo, vegetación de la zona en Estudio. Mostrando que nuestros resultados son de aplicación directa al Proyecto. This document presents the methodological basis to determine the stability of slopes, in one of the roads of penetration with increased growth of vehicular traffic; for this reason their importance in the construction of a paved to connect the peoples of the northern part of the Peru. We also expose the different processes of landslides or mass movements that occur on the slopes; In addition to the factors that influence the analysis of slope stability, to design methods for the verification of the condition of stability and possible methods of stabilization. Finally, an analysis of stability of slope to the Sector of the Km. 17+200 Km. 18+600 of the project will be through the method selected; We have considered as base parameters and characteristics: morphologic, lithological, weather, soil, vegetation in the study area. Showing that our results are directly applicable to the project.

The thesis called The Design of Nedašova Lhota Landslide Securing concentrates on the basic analysis of the problems connected with landslides and safety factors needed for the slopes stability. At the same time it presents a concrete solution to the given practical task, where the slope stability, the causes leading to the landslide and the subsequent redevelopment in view of financial requirements are discussed.

No description available.

A research program was undertaken to quantify the effect of flow induced erosion on the stability of natural river banks along the Red River in Manitoba. The Erosion Measurement Device (EMD) was designed and built in the Geotechnical Laboratory of University of Manitoba to approximate the erosion rate profiles of soil samples from nine sites along the RedRiver. Two simulations of a natural flood event and one of the same flood with the operation of the Floodway were then used to determine the difference in the lower toe erosion and the slopes reduction of the global factor of safety. These results indicate that the operation of the Floodway does not have negative impact on the stability of river banks upstream of the Floodway inlet.

L'ingénierie écologique, qui est décrite comme «la gestion de la nature», a d'abord été proposée par Odum en 1971. Dans les dernières décennies, l'ingénierie écologique a été largement consacrée à lutter contre l'érosion des sols et les mouvements de masse, tout en permettant d'assurer la durabilité des écosystèmes. L'objectif de cette thèse est d'évaluer l'impact de peuplements forestiers sur la stabilité de pentes de dimension finie, en considérant à la fois les effets mécaniques et hydrologiques des racines peu profondes contre les glissements de terrain. Deux sites forestiers monospécifiques et équiennes, plantés respectivement de Robinia pseudoacacia et Platycladus orientalis, ont été sélectionnés sur le Plateau du Loess en Chine et utilisés comme sites d'étude. Le Facteur de Sécurité (FoS) de ces pentes ont été calculées en utilisant un modèle éléments finis 2D qui prend en compte la distribution des racines dans les couches superficielles du sol.Des mesures de terrain et des tests de laboratoire ont été effectués afin d'estimer les principaux paramètres du modèle, à savoir la distribution des surfaces relatives de racines dans le sol (Root Area Ratio), la résistance à la traction des racines, ainsi que les propriétés mécaniques et hydrologiques du sol nu. La contribution des racines à la résistance au cisaillement du sol a été considérée par l'intermédiaire d'une « cohésion additionnelle » calculée à l'aide de modèles fournis par la littérature. Six modèles existants ont été testés. Cette thèse est composée de deux chapitres principaux portant sur: (1) l'effet mécanique de l'hétérogénéité spatiale de la distribution des racines à l'échelle de pente; (2) l'influence de la distribution des racines sur le couplage entre la diffusion de l'eau interstitiel et les contraintes mécaniques dans le sol et son impact sur la stabilité des pentes.Les simulations amènent aux conclusions principales suivantes: (1) les pentes en terrasse sont en théorie 20% plus stables que les pentes rectilignes, sans tenir compte des effets hydrologiques; (2) le FoS atteint une valeur asymptotique lorsque l'on augmente la cohésion des racines; (3) les variations de la cohésion des racines observées sur le terrain ont peu d'effet sur la stabilité des pentes. Toutefois le renforcement de la partie basse des pentes, où les racines ont un plus grand impact positif sur le FOS, peut permettre de diminuer le risque de glissement; (4) l'effet des fortes précipitations sur la stabilité de la pente pourrait probablement être atténué par la présence de racines, mais cet effet dépend des caractéristiques des racines et de leur influence sur le débit d'eau dans le sol. / Ecological engineering, which is described as ‘the management of nature', was first proposed by Odum in 1971. In the past few decades, ecological engineering has been largely devoted to combat soil erosion and mass movement all over the world, because of its benefit on sustainable ecosystems. The objective of this thesis is to evaluate the impact of forest stands on the stability of finite slopes, considering both the mechanical and hydrological effects of roots against shallow landslides. Two monospecific and even-aged forest sites planted with Robinia pseudoacacia and Platycladus orientalis respectively were selected on the Loess Plateau of China and used as study sites. Slope Factors of Safety were calculated using a 2D finite element model that takes into account the distribution of roots in the shallow layers of soil.Field site experiments and laboratory tests were performed in order to estimate the main parameters of the model, i.e. distribution of root area ratio within the soil, root tensile strength, as well as bare soil mechanical and hydrological properties. The contribution of roots to soil shear strength was considered through an additional cohesion calculated with models provided by the literature. Six existing models were tested. This thesis is composed of two main chapters that make the focus on : (1) the mechanical effect of the spatial heterogeneity of root distribution at the slope scale; (2) the influence of root distribution on the coupling between pore fluid diffusion and mechanical stress and its impact on slope stability. This study brings to the following main conclusions: (1) terraced slopes were 20% more stable than rectilinear slopes, disregarding the differences in hydrological regimes between the two sites; (2) FoS could reach an asymptotic value when increasing root additional cohesion; (3) variations of the actual root cohesion do not affect much slope stability. However more attention should be given to the reinforcement of the bottom part of the actual slopes, where roots have a larger positive impact on the FoS; (4) the effect of heavy precipitations on slope stability could probably be overcome or at least mitigated by root system network, but this depends on root characteristics and their resulting effect on soil water flow.

This document is focused on the elucidation of embankment deformation nearby žst. Valašská Polanka, with subsequent proposal of remediation measures, for which the own software and commercial software Plaxis 2D were used.

For the most recent and correct article, please click here: http://ascelibrary.org/doi/abs/10.1061/9780784412787.086 This study examines the use of performance-based approaches in liquefaction hazard analysis. Two new methods of performance-based liquefaction initiation analysis are proposed which use the works of Juang et al. (2012) and Boulanger and Idriss (2012). Further advances are made by incorporating the performance-based magnitude scaling factors as proposed by Cetin et al. (2012). Using these new equations a comparative study is made between the three methods. Further comparisons are made between the performance-based approaches and the more widely used deterministic approaches. The comparisons reveal that on average for the 11 sites used in this study, the performance-based approaches tend to be slightly less conservative than deterministic approaches overall, with large differences possible for some locations in the country. They also reveal that the newer performance-based approaches are generally less conservative than the approach proposed by Kramer and Mayfield (2007). Some cases where this relationship does not hold true and the new relationships are more conservative are outlined.