Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The soil is the base which supports several human elements and activities, such as agriculture and livestock. Therefore, it is a vital component of the ecosystem in which physical, chemical and biological processes and cycle transformations occur. In the municipality Gaurama, Rio Grande do Sul, and in other cities of our country, the local economy is strongly linked to agriculture activity being still responsible for an intense use of soil associated to a low or almost non-existence practice which aims to preserve the basic properties of natural resources leading to a great contribution for the ecosystem degradation. In such context, the proposition of studying slope management through analyses of soil aggregate stability in a toposequence has as objective to contribute for the importance of the comprehension that the pedological cover has in the slope morphological analysis as well as in the installation of three drillings and trenches above the slope in order to analyze morphological characteristics of the pedological volumes of the trenchings 1, 2 and 3, the distribution of particles, consistency limit and aggregate stability by humid via. This research was based on the deductive method. The granulometric analysis of the pedological volumes demonstrated similar characteristics between the T1 and T3 concerning the diameter of the particles, with the predominance of silt and clay fractions, as well as the similar values for the consistency limits and aggregate stability. In the T2, the sand fraction kept itself in balance with the others, not having any abrupt predominance of a granulometric fraction over the other ones. The consistency limits showed that the T2 presents a lower liquid and plastic limit which give it a higher susceptibility to erosive processes due to this soil profile which requires a lower amount of vain to reach a fluid behavior. The higher rates of soil aggregation occurred in the superficial pedological volumes. It was found that the V3 in Trench 2 had the lowest aggregate stability in the entire toposequence of the slope in this research, which shows that the modeling control process of the relief in the medium third and medium lower third of the slope receives a higher inference of this volume. / O solo é a base de sustentação de diversos elementos e atividades humanas, entre as quais se destacam a agricultura e a pecuária e é portanto um componente vital do ecossistema, no qual ocorrem processos e ciclos de transformações físicas, químicas e biológicas. No município de Gaurama, Rio Grande do Sul, assim como em diversos outros municípios do nosso país, a economia local encontra-se fortemente vinculada à atividade agropecuária, a qual ainda é responsável por um uso intenso do solo associada à baixa ou, muitas vezes, inexistente aplicação de práticas que visam conservar as propriedades básicas dos recursos naturais, contribuindo assim com a degradação do ecossistema. Nesse contexto, a proposta de estudar a conformação de vertentes a partir da análise da estabilidade de agregados do solo em uma topossequência teve como objetivo contribuir para a compreensão da importância que o manto pedológico imprime para a análise morfológica das vertentes, além da instalação de três trincheiras e três tradagens sobre a vertente, a fim de analisar as características morfológicas dos volumes pedológicos das trincheiras 1, 2 e 3, a distribuição de partículas, limites de consistência e a estabilidade de agregados, via úmida. O método de pesquisa utilizado foi o dedutivo. A análise granulométrica dos volumes pedológicos evidenciou características semelhantes entre a T1 e a T3 em relação ao diâmetro de partículas, com o predomínio das frações silte e argila, bem como valores semelhantes para os limites de consistência e estabilidade de agregados. Na T2 a fração areia manteve-se em equilíbrio com as demais, não havendo predomínio abrupto de uma fração granulométrica sobre as demais. Os limites de consistência permitiram inferir que a T2 apresenta menor limite de liquidez e plasticidade o que lhe confere maior suscetibilidade frente à ocorrência de processos erosivos, pois seu perfil necessita de menor quantidade de precipitação pluviométrica para atingir o comportamento de fluído. A ocorrência dos maiores percentuais de agregação do solo ocorreu no volume pedológico superficial. Constatou-se que o V3 da trincheira 2 apresentou a menor estabilidade de agregados de toda a topossequência da vertente de estudo, o que evidencia que o processo de controle do modelado do relevo no terço médio e médio inferior da vertente recebe forte inferência deste volume.

[pt] São abordados alguns aspectos relativos à execução de análises probabilísticas em projetos de geotecnia. Apresenta-se um resumo dos conceitos de probabilidade e estatística, utilizados ao longo do trabalho. Descreve-se uma metodologia para a obtenção dos dados necessários à análise probabilística, incluindo a quantidade e a localização de amostras, o cálculo das médias e variâncias dos parâmetros do solo e a quantificação das incertezas relativas a estes valores. Apresenta-se o procedimento de execução dos três métodos probabilísticos mais utilizados em geotecnia com ênfase especial para o Método do Segundo Momento de Primeira Ordem. São executadas análises probabilísticas considerando, separadamente, variações de altura e inclinação de um talude de mineração sob condições drenadas. Avalia-se também a aplicação da metodologia de análise probabilística em situações não-drenadas, através da análise da estabilidade de um quebra-mar sobre argila mole. / [en] Some aspects about probabilistic analysis of stability in geotechnical engineering are studied in this thesis. A summary about basic concepts of probability and statistics used along this work is presented. The methodology for obtaining the data needed for probabilistic analysis is described, including quantity and localization of samples, computation of mean and variance of soil properties and determination of uncertainties about these values. The procedures of three probabilistic methods which are useful in geotechnics are presented, with special emphasis on the first order second moment method (FOSM). Probabilistic analysis are made considering independent changes of height and inclination of a mine slope under drained conditions. The application of probabilistic analysis of a breakwater above a soft clay deposit under undrained conditions is also presented. / [es] Se abordan algunos aspectos relativos a la ejecución de análisis probabilístico en proyectos de geotecnia. Se presenta un resumen de los conceptos de probabilidades y estadísticas, utilizados a lo largo del trabajo. Se describe una metodología para la obtención de los datos necesarios para el análisis probabilístico, incluyendo la cantidad y la localización de las muestras, el cálculo de las medias y variancias de los parámetros del suelo y la cuantificación de los errores relativos a estos valores. Se presenta el procedimientode ejecución de los tres métodos probabilísticos más utilizados en geotecnia con énfasis especial para el Método del Segundo Momento de Primer Orden. Se realizan análisis probabilísticos considerando, separadamente, variaciones de altura e inclinación de un talud de mineración en condiciones drenadas. También se evalúa la aplicación de la metodología de análisis probabilística en situaciones no-drenadas, a través de el análisis de la estabilidad de un quebra olas sobre arcilla blanda.

Oil shale industry in Estonia is looking at other mining technologies as alternative to strip mining and room and pillar mining methods. One such alternative to the room and pillar method is the punch-longwall mining method. Enefit Kaevandused AS, one of the major oil shale companies in Estonia, plans to employ this technology in exploiting some of its resources in the near future. This thesis examines the different stability problems related to the planned punch-longwall mining project in Narva oil shale mine. Determining optimal chain pillar dimensions and stability of the punch-longwall highwall slope are the main objectives of this project. Rock mechanical analyses have been done and recommendations are made based on the rock mechanical aspect of the mining process. Taavi Lõhmuste is responsible for the chain pillar stability analysis and Ott Oisalu for the punch-longwall highwall slope stability analysis. It is essential to understand the geology of a certain area in order to make accurate stability assessments. Because of the previously stated requirements, the geology of Estonian oil shale deposit is examined in the first part of the thesis in order to determine the geological and rock mechanical conditions to set the foundation for further analyses. In conclusion, for the part of the highwall slope, a properly designed barrier pillar plays a key role in the stability of the slope. After reviewing and analyzing the results of both highwall slope numerical models, it can be stated that the minimum length for the barrier pillar that still will yield in stable highwall slope is 65 meters. For the part of the chain pillars, in conclusion, it can be determined that optimal chain pillar dimensions that should be suitable, from the stability standpoint, are 6x6 meters for 3-entry system and 7x7 meters for 2-entry system (length x width).

Les séismes sont connus comme des catastrophes naturelles destructrices et meurtrières. Particulièrement dans les régions montagneuses, les effets des séismes sont encore beaucoup plus aggravés à cause des effets de site topographiques. La présence d'une pente est à l'origine d'une amplification du signal sismique notamment dans le voisinage de la crête. De nombreux séismes anciens tels que le séisme de Lambesc (1909, Ms=6.2) qui a conduit à la destruction du village de Rognes (Bouches-du-Rhône, France), ou plus récemment le séisme d'Athènes en Grèce (1999, Ms=5.9) qui a endommagé la ville d'Adames ainsi que les séismes de Chichi à Taiwan (1999, Mw=7.6), du Salvador (2001, Mw=7.6) et du Sichuan (2008, Mw=7.9) responsables de très nombreux glissements de terrain particulièrement catastrophiques sont des exemples représentatifs. Les investigations post-sismiques ont montré une contribution importante des effets de site topographiques au bilan des dommages humains et matériels. Dans le but d'améliorer les connaissances de ce phénomène, de nombreuses simulations numériques ont été réalisées sur des modèles de versant isolés en utilisant le logiciel FLAC 2D (Itasca). Les résultats obtenus ont été analysés en considérant plusieurs critères comme les facteurs d'amplification, les surfaces et les dimensions des zones d'amplification ainsi que la distribution spatiale de ces zones dans le massif de versant. Des études paramétriques ont permis de mettre en évidence le rôle principal de la fréquence adimensionnelle, rapport de la hauteur du versant à la longueur d'onde du signal sismique, dans l'évaluation des effets de site topographiques. Ces résultats montrent également que la pente est le deuxième paramètre important, suivie du coefficient de Poisson et de la géométrie de la crête et du pied de la pente.Ces résultats numériques ont également permis de définir des relations empiriques, nommées ANS, qui permettent d'estimer les effets de site topographiques selon les différents critères d'interprétation. Ces formules sont adaptées pour les signaux sismiques avec une bande de fréquences prédominantes relativement étroite. Pour les autres cas, la Méthode de Décomposition des ondes (MD) a été développé dans ce travail. Cette méthode est basée sur la décomposition du signal complexe multi-fréquentiel en plusieurs ondes mono-fréquentielles par transformée de Fourier. L'effet du signal complexe est alors évalué en faisant une combinaison des effets individuels de chaque onde élémentaire. Ces approches développées dans ce travail (ANS et MD) permettent d'évaluer les effets de site topographiques, en tenant compte de plusieurs paramètres géomorphologiques et sismiques du massif de versant ainsi que du contenu fréquentiel du signal sismique, sans avoir recours à des simulations numériques. / Earthquakes are known as destructive and murderous natural catastrophe. Particularly in the mountainous regions, the effects of earthquakes are still much aggravated due to the topographic site effects. The presence of a slope causes an amplification of the seismic signal, particularly in the vicinity of the crest. Numerous earthquakes in the past such as the 1909 Lambesc earthquake (Ms=6.2) which led to the destruction of the Rognes village (Bouches-du-Rhône, France), or more recently the 1999 Athens, Greece earthquake (Ms=5.9) which damaged the Adames city as well as the 1999 Chichi, Taiwan earthquake (MW=7.6), the 2001 El Salvador earthquake (MW=7.6) and the 2008 Sichuan earthquake (MW=7.9) responsible for numerous catastrophic landslides are representative examples. Post-seismic investigations demonstrated a significant contribution of topographic site effects on the human and material damage assessment.In order to improve the knowledge of this phenomenon, numerous numerical simulations were performed on the step-like slope models by using the FLAC 2D software (Itasca). The obtained results were analyzed by considering various criteria such as amplification factors, dimensions and area of amplification zones as well as spatial distribution of these zones inside the slope mass. The parametric analyses allow underlining the principal role of the dimensionless frequency, ratio of the slope height to the wavelength of the seismic signal, in the evaluation of topographic site effects. These results also show that the slope angle is the second important parameter, followed by the Poisson's ratio and the geometry of the crest and of the toe of slope.These numerical results allow pointing out empirical equations, called ANS, which can be used to estimate the topographic site effects according to different interpretation criteria. These formulas are suitable for seismic signals with a relatively narrow band of predominant frequencies. For other cases, the method concerning decomposition of seismic incident wave (MD) was developed in this work. This method is based on the decomposition of the complex multi-frequency seismic signal into multiple mono-frequency waves by using Fourier transform. The effect of the complex signal is then evaluated through a combination of the effects of elementary waves. The approaches developed in this work (ANS and MD) allow evaluating the topographic site effects, by taking into account geomorphologic and seismic parameters of the slope as well as the frequency content of the seismic signal, without recourse to numerical simulations.

In this thesis, the failures that occurred during the construction of the Jamuna Bridge Abutment in Bangladesh have been investigated. In particular, the influence of heterogeneity on slope stability has been studied using statistical methods, random field theory and the finite element method. The research is divided into three main parts: the statistical characterization of the Jamuna River Sand, based on an extensive in-situ and laboratory database available for the site; calibration of the laboratory data against a double-hardening elastoplastic soil model; and stochastic finite element slope stability analyses, using a Monte Carlo simulation, to analyse the slope failures accounting for heterogeneity. The sand state has been characterised in terms of state parameter, a meaningful quantity which can fully represent the mechanical behaviour of the soil. It was found that the site consists of predominantly loose to mildly dilative material and is very variable. Also, a Normal distribution was found to best represent the state parameter and a Lognormal distribution was found to best represent the tip resistance.The calibration of the constitutive model parameters was found to be challenging, as alternative approaches had to be adopted due to lack of appropriate test results available for the site. Single-variate random fields of state parameter were then linked to the constitutive model parameters based on the relationships found between them, and a parametric study of the abutment was then carried out by linking finite elements and random field theory within a Monte Carlo framework.It was found that, as the degree of anisotropy of the heterogeneity increases, the range of structural responses increases as well. For the isotropic cases, the range of responses was relatively smaller and tended to result in more localised failures. For the anisotropic cases, it was found that there are two different types of deformation mechanism. It was also found that, as the vertical scale of fluctuation becomes bigger, the range of possible structural responses increases and failure is more likely. Finally, it was found that the failed zones observed during the excavation of the West Guide Bund of the Jamuna Bridge Abutment could be closely predicted if heterogeneity was considered in the finite element analyses. In particular, it was found that, for such a natural deposit, a large degree of anisotropy (in the range of 20) could account for the deformation mechanisms observed on site.

Wind-induced damages on low-slope roofs are a major and common problem that many buildings located in high wind areas suffer from. Most of these damages are initiated when the metal roof edge fails first, leading to overall roof failure. This is because peak wind pressures occur at the edges and corners of low-slope roof buildings. Currently, there are not enough wind design guidelines for the Canadian roofing community to quantify the dynamic wind uplift resistance of the roof edge system. The objective of this research is to evaluate the effect of wind-induced loads on roof edges using a finite element model, verify the numerical results with those obtained from controlled experiments, and perform parametric investigations for various design variables. In this research, the overall roof edge system was modelled using the commercial finite element software package ABAQUS, by simulating the roof edge system with shell elements and applying a uniform static pressure against the face of the edge cleat or coping. Results of the modelling were compared to the experimental ones in terms of deflection of the coping under uniform pressure. The results of the numerical model and the experiments show a good agreement. Furthermore, a parametric analysis of the system was conducted under the effect of varying parameters. i.e., coping gauge, nail spacing, coping and cleat length and wind and thermal load application.

The CAREN-Extended system is a fully immersive virtual environment (VE) that can provide stability-challenging scenarios in a safe, controlled manner. Understanding gait biomechanics when stability is challenged is required when developing quantifiable metrics for rehabilitation assessment. The first objective of this thesis was to examine the VE’s technical aspects to ensure data validity and to design a stability-challenging VE scenario. The second and third objectives examined walking speed changes and kinematic strategies when stability was challenged for able-bodied and unilateral transtibial amputees. The results from this thesis demonstrated: 1) understanding VE operating characteristics are important to ensure data validity and to effectively design virtual scenarios; 2) self-paced treadmill mode for VEs with multiple movement scenarios may elicit more natural gait; 3) gait variability and trunk motion measures are useful when quantitatively assessing stability performance for people with transtibial amputations.

This study investigates the lithological characteristics, and lateral and vertical facies trends of poorly understood, deep-marine matrix-rich sedimentary rocks. Two laterally extensive, well-exposed outcrops of slope and proximal basin floor deposits were investigated from the Neoproterozoic Windermere Supergroup. Significantly, matrix-rich beds have been found to undergo the same lateral trends (over ~200-650 m) in both outcrops. Initially, thicker, clayey sandstone transitions laterally to a bipartite bed with the development of an upper, planar-based, more matrix-rich unit. Further laterally, the basal unit progressively thins until it pinches out, and all that remains is the upper, more matrix-rich unit – a sandy claystone. It too thins and then pinches out. Draping the entire transect is a thin, matrix-poor structured unit overlain by a mudstone or claystone cap. These trends are interpreted to reflect a progressive but rapid lateral evolution of flow structure controlled primarily by particle settling, namely sand, from mud-rich avulsion-related flows.

Les systèmes méandriformes construisent, à long terme, des architectures sédimentaires composées de corps poreux disséminés dans un volume de sédiments peu perméables. Ces corps sont susceptibles de contenir des ressources naturelles. Afin d'optimiser leur exploitation, il importe d'estimer la répartition et la connectivité de ces corps. À cet effet, Mines-Paristech développe Flumy, un logiciel de modélisation par processus de ces architectures . Cette thèse vise à améliorer la simulation de la migration dans Flumy en introduisant une influence.Pour cela, trois différents modèles ont été reliés entre eux et comparés. Le premier (modèle à pente constante) est celui actuellement en place dans Flumy, héritier des travaux de [Ikeda 1981] et dans lequel la pente de la surface du cours d'eau est constante. Le deuxième (modèle à pente variable) fut proposé par [Lopez 2003]. Il attribue à la surface libre la pente locale de la topographie. Enfin, un dernier modèle (modèle Saint Venant) a été élaboré en modifiant le précédent. L'écoulement moyen, initialement calculé sous une surface libre connue, est désormais obtenu par résolution des équations de Saint Venant sur un fond connu. Ces trois modèles ont été appliqués à la migration à long terme de méandres libres. Les modèles à pente constante et à pente variable ont également été utilisés pour reproduire les méandres confinés de deux rivières canadiennes, la Beaver et la Red Deer.Les résultats montrent un développement plus réaliste des méandres simulés avec le modèle à pente variable que de ceux simulés avec le modèle à pente constante. Cette amélioration est observable dans les méandres isolés (ralentissement de la vitesse d'extension) et dans les trains de méandres (confinement en ceintures de méandres). Le modèle à pente variable permet également une meilleure reproduction de la morphologie des méandres confinés. L'utilisation du modèle Saint Venant apporte les mêmes améliorations dans la simulation des méandres libres, quoique moins prononcées. Il permet surtout de construire une surface libre physique sur une grande variété de fonds, résolvant ainsi une limite identifiée dans le modèle à pente variable. / Over a long time, Meandering systems build sedimentary architectures composed of porous bodies scattered inside a volume of low-permeability sediments. These bodies may contain natural resources. In order to optimize their mining, it is essential to estimate the distribution and connectivity of such bodies. To this end, Mines ParisTech develops Flumy, a process-based model simulating the formation of these architectures. This thesis aims to improve the simulation of the migration in Flumy by taking into consideration the influence of the local slope.For this purpose, three distinct models were considered in conjunction, and compared. The first one (constant slope model), which constitutes the basis of the current Flumy version, was originally developed by [Ikeda 1981]. The second model (variable slope model), developed by [Lopez 2003], assigns to the free surface the slope of the surrounding topography. Finally, the last model (Saint-Venant model) has been derived from the variable slope model. Initially calculated under a known free surface, the mean flow in each cross-section is now obtained by solving the Saint-Venant equations over a known river bed. Each of those three models has been applied to the simulation of free meanders. Moreover, the constant-slope and variable slope models have been used to reproduce the confined meanders of two Canadian streams.The results point to a more realistic meanders development using the variable slope model than with the constant slope model. This improvement can particularly be observed in individual meanders, whose rate of extension decreases with the age. It is also noticeable in the overall river behavior, which self-confines in a meander belt. The specific morphology of the confined meanders is also better reproduced using the variable slope model than with the constant slope model. Lastly, though a lesser extent, the Saint-Venant model shows the same advantages than the variable slope model. In addition, it allows the construction of a physically meaningful free surface over a wide range of beds and, in doing so, resolves a limit of the variable slope model.

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