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.

Les travaux présentés portent sur l'étude de modèles numériques multi-fidèles, déterministes ou stochastiques. Plus précisément, les modèles considérés disposent d'un paramètre réglant la qualité de la simulation, comme une taille de maille dans un modèle par différences finies, ou un nombre d'échantillons dans un modèle de Monte-Carlo. Dans ce cas, il est possible de lancer des simulations basse fidélité, rapides mais grossières, et des simulations haute fidélité, fiables mais coûteuses. L'intérêt d'une approche multi-fidèle est de combiner les résultats obtenus aux différents niveaux de fidélité afin d'économiser du temps de simulation. La méthode considérée est fondée sur une approche bayésienne. Le simulateur est décrit par un modèle de processus gaussiens multi-niveaux développé dans la littérature que nous adaptons aux cas stochastiques dans une approche complètement bayésienne. Ce méta-modèle du simulateur permet d'obtenir des estimations de quantités d'intérêt, accompagnés d'une mesure de l'incertitude associée. L'objectif est alors de choisir de nouvelles expériences à lancer afin d'améliorer les estimations. En particulier, la planification doit sélectionner le niveau de fidélité réalisant le meilleur compromis entre coût d'observation et gain d'information. Pour cela, nous proposons une stratégie séquentielle adaptée au cas où les coûts d'observation sont variables. Cette stratégie, intitulée "Maximal Rate of Uncertainty Reduction" (MRUR), consiste à choisir le point d'observation maximisant le rapport entre la réduction d'incertitude et le coût. La méthodologie est illustrée en sécurité incendie, où nous cherchons à estimer des probabilités de défaillance d'un système de désenfumage. / The presented works focus on the study of multi-fidelity numerical models, deterministic or stochastic. More precisely, the considered models have a parameter which rules the quality of the simulation, as a mesh size in a finite difference model or a number of samples in a Monte-Carlo model. In that case, the numerical model can run low-fidelity simulations, fast but coarse, or high-fidelity simulations, accurate but expensive. A multi-fidelity approach aims to combine results coming from different levels of fidelity in order to save computational time. The considered method is based on a Bayesian approach. The simulator is described by a state-of-art multilevel Gaussian process model which we adapt to stochastic cases in a fully-Bayesian approach. This meta-model of the simulator allows estimating any quantity of interest with a measure of uncertainty. The goal is to choose new experiments to run in order to improve the estimations. In particular, the design must select the level of fidelity meeting the best trade-off between cost of observation and information gain. To do this, we propose a sequential strategy dedicated to the cases of variable costs, called Maximum Rate of Uncertainty Reduction (MRUR), which consists of choosing the input point maximizing the ratio between the uncertainty reduction and the cost. The methodology is illustrated in fire safety science, where we estimate probabilities of failure of a fire protection system.

[pt] Este trabalho apresenta a utilização de métodos de equilíbrio limite em conjunto com métodos numéricos pela abordagem probabilística, para avaliação da estabilidade de uma barragem de rejeitos de mineração de ferro situada no quadrilátero ferrífero, no Estado de Minas Gerais. Foram conduzidas análises fazendo uso dos métodos de Bishop Simplificado (1955) e Morgenstern e Price (1965), além de análises numéricas de tensão vs deformação pelo método dos elementos finitos. Os campos de poropressão gerados no modelo numérico em dois momentos distintos da obra foram exportados para os modelos de equilíbrio limite, de forma que ambas análises fossem realizadas em condições piezométricas similares. Para as análises probabilísticas foram adotados os métodos FOSM (First Order Second Moment) e Monte Carlo. São apresentandos os conceitos básicos de análises de estabilidade determinísticas e probabilísticas, abrangendo os métodos de cálculo de FS, fundamentos de probabilidade e estatística e conceitos de modelagem numérica. Este estudo aborda também os princípios construtivos de barragens de rejeito de mineração, além da aplicação dos métodos probabilísticos para avaliação da estabilidade de uma barragem de rejeitos, construída pelo método de jusante. Os resultados indicaram que a consideração de uma superfície de ruptura livre foi fator preponderante na influência dos parâmetros na PR (Probabilidade de Ruptura). Concluiu-se também que os método de cálculo de FS teve maior influência no valor da PR do que as condições piezométricas da fundação. / [en] This work presents the use of limit equilibrium (LEM) and numerical methods by the probabilistic approach, in order to evaluate the stability of an iron ore tailings dam located in Minas Gerais s iron quadrangle. LEM analyzes were carried out using the Simplified Bishop (1955) and Morgenstern and Price (1965) methods, in addition to stress vs strain analyzes with the finite element method. The pore pressure fields generated in the numerical model at two distinct construction stages were exported to the limit equilibrium models in order to guarantee that both analyzes were performed on the same piezometric conditions. For the probabilistic analyzes the FOSM (First Order Second Moment) and Monte Carlo methods were applied. The basic concepts of deterministic and probabilistic stability analysis are presented together with the fundamentals of statistics and probability, FoS (Factor of Safety) calculation methods, as well as numerical modeling concepts. This work also addresses the definition and construction principles of tailings dams. This study presents an application of probabilistic methods to assess the stability of a tailings dam built and heightened by the downstream method. The results indicate that the consideration of a free failure surface was the decisive factor to the magnitude of the influence of each parameter on the PF (Probability of Failure). It was also concluded that the FoS calculation methods had a greater influence on the PF than the foundation s piezometric conditions.

Climate change results to more extreme and frequent flood events that induce extra risk to flood protection structures such as levees. Thus, estimation of the probability of levee failure is of utmost importance when it comes to structural safety and flood risk assessment. This master thesis focuses on the estimation of the probability of levee failure owing to backward erosion at the foundation of the levee. For the estimation of the probability of failure three breach models of different complexity were developed and site-specified data were used from the Paglia river area and an assessment of the results followed. Besides the breach models, a 2-D hydraulic model was also built where breach scenarios were used to assess the associated flood risk. The results showed that the complexity of the breach model plays significant role to the estimated probability of failure. The simplest model estimated the lowest probability, while the complex the highest. Consequently, the associated to the complex model flood risk was higher than the other two. / Klimatförändringarna är ett allmänt problem som bland annat resulterar i ökad risk för extrema hydrologiska händelser. Av dessa extrema händelser är översvämningar bland de mest förekommande. För att tackla problemen med översvämningsriskerna används skyddsvallar som en av de vanligaste anläggningarna bland olika översvämningsskydd. Vid ett tillräckligt högt flöde kan dock den ökade belastningen på skyddsvallen orsaka att skyddsvallen havererar. En skyddsvall kan haverera på grund av flera fysikaliska fenomen, varav de vanligaste är inre erosion, otillräcklig släntstabilitet samt överspolning. Risken för att en skyddsvall havererar, det vill säga brottrisken, kan beräknas med olika metoder. Sannolikhetsbaserade metoder har nyligen växt fram som ett allt viktigare tillvägagångssätt. Det här examensarbetet handlar om brottsannolikhetsberäkningar för skyddsvallar i syfte att kartlägga översvämningsrisker. Arbetet fokuserar på fenomenet med inre erosion i skyddsvallars grundläggning. Det praktiska exemplet i examensarbetet studerar nybyggda skyddsvallar utmed den italienska floden Paglia längs en flodsträcka om 4,5 km mellan städerna Ciconia och Orvieto Scalo i regionen Umbria i centrala Italien. Ur ett hydrogeologiskt perspektiv karaktäriseras regionen av fint jordmaterial, med inslag av slutna akviferer. Sannolikhetsberäkningar med hjälp av ramverket för Monte Carlo-analys genomfördes för tre olika modeller för att beskriva inre erosion i skyddsvallarna till följd av ett 200-årsflöde. De tre olika numeriska modellerna kännetecknades av olika grad av komplexitet. Den enklaste modellen baserades på en metod av Mazzoleni et al. (2015) och tog endast hänsyn till skyddsvallens porositet. Den mellankomplexa modellen var baserad på metoden ifrån Khilar et al. (1985). Den mest komplexa modellen var tidsberoende och baserades på metoderna från Sellmeijer et al. (2011) och Scheuermann (2005), för att ta hänsyn till de två ömsesidigt beroende fenomenen bakåterosion, så kallad ”piping” och läckage, så kallat ”seepage”, vilka tillsammans ger upphov till inre erosion. Resultaten visar att graden av komplexitet i den numeriska modellen spelar en viktig roll när det gäller brottsannolikheten för skyddsvallars grundläggning. Den enklaste modellen beräknade en lägre brottsannolikhet än de andra två modellerna, och den mest komplexa modellen beräknade högst brottsannolikhet av de tre modellerna. Vidare visar resultaten på att några parametrar har en stor inverkan på brottsannolikheten. Dessa är bland annat partikeldiametern som påverkar skjuvhållfastheten i materialet, permeabiliteten, jordlagrets tjocklek under skyddsvallen samt strömningsvaraktigheten. Parametern strömningsvaraktighet kan endast beaktas i tidsberoende modeller, vilket är en av fördelarna med den mest komplexa modellen i denna studie. Förutom de numeriska brottsannolikhetsmodellerna byggdes en tvådimensionell hydraulisk modell upp för att kartlägga de resulterande översvämningsriskerna. Tre olika haveriscenarier studerades för att representera de tre brottsannolikhetsmodellerna. Dock visade det sig att den enklaste av de tre modellerna beräknade så låg brottsannolikhet att det inte var meningsfullt att studera de resulterande översvämningsriskerna enligt den enklaste brottsannolikhetsmodellen i den hydrauliska modellen. Av de två mer komplexa brottsannolikhetsmodellerna visade det sig att den mest komplexa av de två gav mer omfattande haverier i skyddsvallarna och dessutom haverier i flera av skyddsvallarna. Vidare gav den mest komplexa modellen upphov till högst vattennivåer bakom de havererade skyddsvallarna. Slutligen kan det nämnas att staden Scalo Orvieto är utsatt för en högre översvämningsrisk än staden Ciconia enligt resultaten i denna studie.

[pt] A análise de estabilidade de poços de petróleo é um passo importante para uma previsão do comportamento geomecânico de poços que ainda serão perfurados e para o entendimento de problemas que possam ter acontecido em perfurações anteriores (a fim de evitar que os problemas se repitam). Muitas complicações que ocorrem ao longo da perfuração de um poço são devido a um dimensionamento falho do peso de fluido de perfuração a ser utilizado. Algumas dessas complicações podem gerar a necessidade da interrupção da perfuração, o que provoca o tempo não produtivo e, consequentemente, o acréscimo de milhões de dólares na soma final dos gastos da operação, devido ao aluguel de equipamentos que são subutilizados nesse momento. As análises de estabilidade são amplamente realizadas de maneira determinística, o que pode acarretar incertezas aos resultados. Este trabalho propõe a análise de estabilidade probabilística de poços de petróleo baseada em dois métodos diferentes: FOSM e SEAM, com o objetivo de fornecer uma janela operacional mais realista para a análise de estabilidade ao longo de toda a trajetória de um poço. As metodologias FOSM e SEAM foram implementadas em código MATLAB pela autora desse trabalho e então foi possível obter os gradientes de colapsos e fratura para um projeto de um poço de petróleo (ao longo de toda sua trajetória). No estudo de caso proposto, foi possível observar que os resultados probabilísticos obtidos – para uma probabilidade de falha da formação de 10% – apresentaram uma previsão mais coerente para o comportamento dos gradientes de colapsos e fratura desse poço do que os resultados determinísticos, de onde se conclui que alguns problemas observados durante a perfuração poderiam ter sido evitados com a utilização dos métodos probabilísticos. / [en] The stability analysis of a wellbore is an important step to predict the geomechanical behavior of wellbores that will be drilled and for understanding problems that may have occurred in wellbores already drilled (in order to prevent problems from happening again). Many unwanted events that occur during the drilling of a wellbore are due to a bad dimensioning of the mud weight used. Some of these complications can bring on the need to interrupt drilling operation, which causes non-productive time and, consequently, the addition of millions of dollars in the final sum of the expenses of the drilling operation, due to the daily rental of equipment that are not used during the non-productive time. The stability analyzes are widely performed with deterministic methods, which can lead to uncertainties in the final results. This paper proposes a probabilistic wellbore stability analysis based on two different methods: FOSM and SEAM, with the purpose of providing a more realistic mud weight window for the stability analysis along the trajectory of the wellbore. The FOSM and SEAM methodologies were developed in MATLAB code by the author of this study and then it was possible to obtain the collapses and fracture gradients for a project of a wellbore (along its entire trajectory). In the case study proposed, it was possible to observe that the probabilistic results - for a failure probability of 10% - presented a more coherent prediction of the behavior of the wellbore s collapses and fracture gradients than the deterministic results, and hence it can be concluded that some of the problems observed during drilling operation could have been avoided with the use of probabilistic methods.

L’incorporation des instruments intelligents dans les boucles de sécurité nous mène vers une sécurité intelligente et les systèmes deviennent des « systèmes instrumentés de sécurité à intelligence distribuée (SISID) ». La justification de l’usage de ces instruments dans les applications de sécurité n’est pas complètement avérée. L’évaluation de la sûreté de fonctionnement de ce type de systèmes n’est pas triviale. Dans ce travail, la modélisation et l'évaluation des performances relatives à la sûreté de fonctionnement des systèmes instrumentés de sécurité (SIS) sont traitées pour des structures intégrant de l’intelligence dans les instruments de terrain. La méthodologie que nous utilisons consiste en la modélisation de l’aspect fonctionnel et dysfonctionnel de ces systèmes en adoptant le formalisme basé sur les réseaux de Petri stochastiques qui assurent la représentation du comportement dynamique de ce type de systèmes. La modélisation est traitée sous la forme d’une approche stochastique utilisant les réseaux d’activité stochastiques SAN (Stochastic Activity Network). L’introduction d’indicateurs de performances permet de mettre en évidence l’effet de l’intégration des niveaux d’intelligence dans les applications de sécurité. La méthode de Monte Carlo est utilisée pour évaluer les paramètres de sûreté de fonctionnement des SIS en conformité avec les normes de sécurité relatives aux systèmes instrumentés de sécurité (CEI 61508 et CEI 61511). Nous avons proposé une méthode et les outils associés pour approcher cette évaluation par simulation et ainsi apporter une aide à la conception des systèmes instrumentés de sécurité (SIS) intégrant quelques fonctionnalités des instruments intelligents / The incorporation of intelligent instruments in safety loops leads towards the concept of intelligent safety and the systems become “Intelligent Distributed Safety Instrumented Systems (IDSIS)”. The justification for using these instruments in safety applications is not fully proven and the dependability evaluation of such systems is a difficult task. Achieved work in this thesis deals with modelling and thus the performance evaluation relating to the dependability for structures which have intelligence in the instruments constituting the Safety Instrumented Systems (SIS). In the modelling of the system, the functional and dysfunctional aspects coexist and the dynamic approach using the Stochastic Activity Network (SAN) is proposed to overcome the difficulties mentioned above. The introduction of performance indicators highlight the effect of the integration of intelligence levels in safety applications. Monte-Carlo method is used to assess the dependability parameters in compliance with safety standards related to SIS (IEC 61508 & IEC 61511). We have proposed a method and associated tools to approach this evaluation by simulation and thus provide assistance in designing Safety Instrumented Systems (SIS) integrating some features of intelligent tools

Made available in DSpace on 2014-06-11T19:22:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-27Bitstream added on 2014-06-13T18:49:27Z : No. of bitstreams: 1 silva_mr_me_ilha.pdf: 2058535 bytes, checksum: 046bcb6196cc4909e675190cc0e21275 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O estudo da confiabilidade operacional de equipamentos se tornou fundamental para as empresas possuírem o devido controle dos seus ativos, tanto pelo lado financeiro quanto em questões de segurança. O estudo da taxa de falha de equipamentos prevê quando as falhas irão ocorrer possibilitando estabelecer atitudes preventivas, porém, seu estudo deve ser realizado em condições de operação estabelecidas e fixas. Os medidores de energia elétrica, parte do ativo financeiro das concessionárias de energia, são equipamentos utilizados em diversas condições de operação, tanto nas condições do fluxo de energia, tais como presenças de harmônicos, subtensões, sobre-tensões e padrões de consumo distintos, quanto pelo local físico de instalação, tais como maresia, temperatura, umidade, etc. As falhas nos medidores eletromecânicos de energia elétrica são de difícil constatação uma vez que a maioria dos erros de medição, ocasionados principalmente por envelhecimento de componentes, não alteram a qualidade da energia fornecida e nem interrompem o seu fornecimento. Neste sentido, este trabalho propõe uma nova metodologia de determinação de falhas em medidores eletromecânicos de energia elétrica ativa. Faz-se uso de banco de dados de uma concessionária de energia elétrica e do processo de descoberta de conhecimento em bases de dados para selecionar as variáveis mais significativas na determinação de falhas em medidores eletromecânicos de energia elétrica ativa, incluindo no conjunto de falhas a operação com erros de medição acima do permitido pela legislação nacional (2010). Duas técnicas de mineração de dados foram utilizadas: regressão stepwise e árvores de decisão. As variáveis obtidas foram utilizadas na construção de um modelo de agrupamento de equipamentos associando a cada grupo uma probabilidade... / The operational reliability study of equipments has become primal in order to enterprises have the righteous control over their assets, both by financial side as by security reasons. The study for the hazard rate of equipments allows to foresee the failures for the equipments and to act preventively, but this study must be accomplished under established and fixed operation conditions. The energy meters, for their part, are equipments utilized in several operating conditions so on the utilization manner, like presence of harmonics, undervoltages and over-voltages and distinct consumption patterns, as on the installation location, like swel, temperature, humidity, etc. Failures in electromechanical Wh-meters are difficult to detect once that the majority of metering errors occurred mainly by aging of components do not change the quality of offered energy neither disrupt its supply. In this context, this work proposes a novel methodology to obtain failure determination for electromechanical Whmeters. It utilizes Wh-databases from an electrical company and of the process of knowledge discovery in databases to specify the most significant variables in determining failures in electromechanical Wh-meters, including in the failure set the operation with metering errors above those permitted by national regulations (2010). Two techniques of data mining were used in this work: stepwise regression and decision trees. The obtained variables were utilized on the construction of a model of clustering similar equipments and the probability of failure of those clusters were determined. As final results, an application in a friendly platform were developed in order to apply the methodology, and a case study was accomplished in order to demonstrate its feasibility.

[pt] Na prática geotécnica, a estabilidade de taludes é atualmente estudada apenas com análises determinísticas, obtendo-se o valor do Fator de Segurança (FS) da estrutura geotécnica. Estas análises são simplificadas, pois fornecem valores de FS sem considerar a variabilidade intrínseca dos solos e rochas. Desprezar as incertezas dos parâmetros geotécnicos pode levar a resultados pouco confiáveis sobre a segurança de taludes. Análises fundamentadas em conceitos estatísticos, chamadas probabilísticas, passam ser mais frequentes na geotecnia por permitirem considerar efeitos da variabilidade inerente aos materiais. Estas análises incorporam elementos estatísticos que possibilitam tratar FS como uma função e estudar suas propriedades. Como resultados finais, os métodos probabilísticos fornecem o índice de confiabilidade (beta) e a probabilidade de ruptura (Pr) da estrutura averiguada. Este trabalho aplica análises determinísticas e probabilísticas de um talude de 200m de altura da Mina do Cauê, Itabira, MG. A estabilidade do talude foi analisada por cinco métodos determinísticos usuais e três probabilísticos (FOSM, EP e MC). Os resultados indicam que a fixação da superfície crítica de ruptura fornece, em geral, valores de beta e Pr semelhantes aos obtidos quando a superfície pode variar livremente. Com a superfície crítica fixa observou-se, também, que os resultados de beta e Pr do talude variam significativamente com o método de equilíbrio limite adotado. Após comparação dos resultados, pode-se recomendar o uso de análises probabilísticas FOSM com base no método de Morgenstern-Price em análises semelhantes ao caso estudado. / [en] In current geotechnical practice, slope stability assessments are usually carried out only based on deterministic methods, obtaining a value of Safety Factor (FS). These analyses are simplified because the FS values do not consider the natural variability of soils and rocks. Disregarding the uncertainties inherent to geotechnical parameters may lead to unreliable results of slope safety. Probabilistic analyses, based on statistical concepts, have become more frequent in geotechnical practice, as they allow incorporating the materials intrinsic variability. These analyses are based on statistical elements that allow treating the FS as a function and studying its properties. The probabilistic methods indicate the reliability index (beta) and the probability of failure (Pr) of the verified geotechnical structure. This work presents deterministic and probabilistic analyses of a 200m high slope at the Cauê Mine, located in Itabira, Minas Gerais, Brazil, with basis on five usual deterministic methods and three probabilistic techniques (FOSM, Point Estimates and Monte Carlo). The results indicate that fixing the critical deterministic surface generally gives values of beta and Pr similar to those achieved when the surface is free to vary. It was also concluded that, with a fixed critical surface, beta and Pr results change significantly, when different Limit Equilibrium methods are adopted. It is recommended to use probabilistic FOSM analysis with Morgenstern and Price stability method in analyses similar to the one presented herein.

The subject of master’s thesis is determination of bridge load-bearing capacity and fully probabilistic approach to reliability assessment. It includes a nonlinear analysis of the specific bridge load-bearing capacity in compliance with co-existing Standards and its stochastic and sensitivity analysis. In connection with durability limit states of reinforced concrete structures, the influence of carbonation and the corrosion of reinforcement on the structure’s reliability is also mentioned.

No description available.