Tesis: "Limit equilibrium"

1

Liu, Ying y 劉影. "Limit equilibrium methods for slope stability analysis". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42576684.

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Liu, Ying. "Limit equilibrium methods for slope stability analysis". Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42576684.

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Garrido, Sureda Nicolás Ignacio. "Dynamic equilibrium in multiple limit order markets: Overlapping". Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/146671.

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Magíster en Economía Aplicada. Ingeniero Civil Industrial
Desarrollamos un modelo de equilibrio dinámico para el fenómeno de Overlapping , donde agentes neutros al riesgo transan un activo de forma continua en libros de órdenes reales mediante órdenes de tipo market y limit . Encontramos que los principales oferentes de órdenes limit se ven beneficiados tanto en la apertura como en el cierre del overlap . Antes del inicio, cargan el libro con órdenes limit lejos de los precios de bid y ask . Al cierre del overlap , obtienen los mejores términos transaccionales del día, alcanzando así su máximo bienestar. Por otro lado, los demandantes de órdenes tipo market tienen su bienestar mínimo durante los primeros minutos de overlap entre los libros de órdenes.

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4

McCombie, Paul F. "Some developments of limit equilibrium analyses in geotechnical engineering". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501625.

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Four journal papers have been selected from the candidate's published research output, to represent his work in developing analytical methods for use in geotechnical engineering design and analysis. Two of the papers contribute to significant advances in the understanding of the behaviour of dry-stone retaining walls, which will lead to greater confidence in the assessment of existing walls and the design of new walls. The other two papers develop optimisation and analysis routines with the aim of supporting the assessment of slope stability, and the design of new cut and built slopes and stabilisation works.

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5

Riarte, Campillay Ítalo Tomás. "Dynamic equilibrium in multiple markets". Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/138559.

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Autor no autoriza el acceso a texto completo de su documento hasta el 15/1/2021.
Ingeniero Civil Industrial
Se presenta un modelo dinámico de múltiples mercados financieros, organizados como limit order markets, en el cual agentes endógenamente toman decisiones óptimas para maximizar el valor esperado de sus ganacias. Los agentes toman sus decisiones considerando incentivos propios, condiciones de mercado, potenciales decisiones de trading futuras y diferentes estrategias adoptadas por otros agentes. Para efectos de la presente investigación, se compara el escenario de un único mercado financiero ( single market ) con un escenario de dos mercados interconectados que compiten por el flujo de órdenes ( multi markets ). Los resultados indican que la posibilidad de transar en múltiples mercados, beneficia ampliamente a agentes sin valoración privada por el activo, ya que buscan oportunidades de transar en ambos mercados, mientras que perjudica el bienestar de agentes con motivación intrínseca para transar, dado que obtienen peores condiciones de negociación. Por otro lado, se observa una reducción en varias medidas de liquidez en multi markets, lo que sugiere la existencia de externalidades positivas asociadas a mercados consolidados.

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6

Aryal, Krishna Prasad. "Slope Stability Evaluations by Limit Equilibrium and Finite Element Methods". Doctoral thesis, Norwegian University of Science and Technology, Department of Civil and Transport Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1868.

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This thesis deals with slope stability evolutions carried out by commonly used limit equilibrium (LE) and finite element (FE) methods. The study utilizes two LE based software (SLOPE/W and SLIDE) and one FE based software (PLAXIS). The principal difference between these two analyses approaches is that the LE methods are based on the static of equilibrium whereas FE methods utilise the stress‐strain relationship or constitutive law.

To fulfil one of the aims of the study, the LE based methods are compared based on the factor of safety (FOS) obtained for various load combinations. The comparison is mainly based on simplified slope geometry and assumed input parameters. Among the LE methods, the Bishop simplified (BS), Janbu simplified (JS) and Janbu GPS methods are compared with the Morgenstern‐Price method (M-PM). The two latter methods satisfy both force and moment equilibriums. In addition, M-PM allows a variable interslice force function. These LE methods are well established for many years, and thus some of them are still commonly used in practice for stability analysis. Simplicity and relatively good results are the advantages of these methods.

The comparative study among the LE methods shows that BSM is as good as M-PM for normal condition in circular shear surface (SS) analysis. Similarly, JSM is as good as M‐PM for plane SS analysis. Moreover, the study shows that BSM is insensitive to interslice forces in circular SS analysis, whereas JSM is insensitive to interslice forces in plane SS analysis.This is true for the analyses without any external forces acting in slopes. With some external forces, both methods may be sensitive to the interslice force function, and thus the analyses may result in either higher or lower FOS compared with M-PM. Even if the M-PM assumes an interslice force function in analysis, the method is found suitable, because the method satisfies both force and moment equilibrium conditions. The comparison between Janbu’s GPS method and the M‐PM shows a very good agreement with nominal difference (<2%) in the FOS.

Moreover, the M-PM has been compared with results from the FE analyses. Compared with the FE (PLAXIS) analyses, the LE (M-PM) analyses may estimate 5 – 14% higher FOS, depending on the conditions of a dry slope and a fully saturated slope with hydrostatic pore pressure distributions. For fully saturated conditions in the slope, inaccurate computation of stresses in LE methods may have resulted in larger difference in the computed FOS.

Since, the FE software is based on stress-strain relationship, stress redistributions are surely better computed even for a complicated problem. This has been found one of the advantages in FE simulations. A parameter study shows that the application of a positive dilatancy angle in FE analysis can significantly improve the FOS (4 - 10%). On contrast, the shear surface optimization in LE (M-PM in SLOPE/W) analysis results in lower FOS, and thus minimizing the difference in FOS compared with FE analysis. Thus, the optimisation of the circular SS in LE analyses and application of dilatancy angle in FE analyses may provide very good agreement in FOS keeping the variations less than 5%.

Instability of natural and built-in slopes has been a serious geotechnical challenge, particularly in mountainous countries like Nepal, where a large number of water-induced disasters are experienced every year. Since the country lies in a relatively active earthquake zone, earthquake events may adversely affect the long-term stability of slopes along the highways, around hydropower installations and elsewhere. The selected case study from the Middle Marsyangdi Hydroelectric Project (MMHEP) in Nepal was carried out, focusing on both the groundwater and earthquake effects on long-term stability of slopes. In addition, the analyses were performed for pore pressure distributions by seepage analyses and pseudo-static and dynamic earthquake events imposed in the case slopes.

Another important contribution of this study has been the investigations of the shear strength parameters for the case study slopes. The investigation ranges from the basic index tests, which were carried out to characterize material properties and establish a basis for building-in the test specimens, to the most advanced triaxial tests. Additionally, both consolidated drained and undrained triaxial tests were conducted, aiming to find any differences in the strength parameters. A total of twenty-four triaxial tests from four different soil samples, taken from the case study slopes, were conducted to define the Mohr-Coulomb failure envelope, and thus obtained the effective shear strength parameters (c’, φ’) for stability evaluations. In addition, the coefficients of permeability were investigated as an important input for seepage analyses.

Two slopes, one located at the dam site and the other at the powerhouse of the MMHEP, were evaluated for long-term stability conditions. The study, carried out using the monitored groundwater table, reveals that the groundwater is the potential destabilizing factor in the slopes. Both hydrostatic pore pressure distributions with phreatic surface correction and seepage analysis were carried out in the stability analysis. The pore pressure distributions from the seepage analyses indicated critically stable slopes particularly at the toe areas. However, a significant improvement in the FOS was found with lowered groundwater table. Moreover, the study, carried out for the pseudo-static analysis with the selected earthquake acceleration coefficient, shows that otherwise stable slopes become critical in earthquake events. However, the case slopes were found to have higher FOS than the recommended minimum value for such conditions. The dynamic earthquake simulations indicate both positive excess pore pressure and suction developed during the earthquakes. The applied earthquake acceleration of 0.15g (35% of PGA, where PGA = 4.2 m/s2)) shows critical conditions in the slopes. Moreover, larger accumulated displacements were found close to the slope surface compared to the inner side of the slopes. In addition, the dynamic analyses further indicate plastic points all over the slopes and increased shear strains in a particular location.

Nevertheless, the difference in FOS found from the LE and FE analyses may have a little interest, if there is a large uncertainty in the input parameters. Therefore, priority should be given to investigate the shear strength parameters and precise mapping of the slope geometry before selecting an appropriate analysis method. Most preferably, a slope should be analyzed by FE methods, else otherwise by LE based M‐PM or GPS method with investigated input parameters.

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7

Potgieter, Jean-Timothy. "Finite element versus limit equilibrium stability analyses for surface excavations". Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/63001.

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Limit equilibrium methods are widely and routinely used in practice. In several codes, limit equilibrium methods are recommended to evaluate the stability of a lateral support systems, such as soil-nails and anchors, to an acceptable defined factor of safety. For decades, limit equilibrium methods have been used successfully in providing an acceptable margin of safety against failure (movements, which can be significantly more complex, is not considered). However, due to the advances in computational power offered by personal computers, finite element modelling has become increasingly accessible. Since the idea immerged of using a strength reduction factor in finite element displacement analyses, an increase in the use thereof to calculate the factor of safety has been observed. However, the use of finite elements has often led to misinterpretation of the results. Several authors have cautioned engineers to the complexities involved in using finite element analyses to model geotechnical problems. Studies have been conducted comparing the use of finite elements to other methods. However, most of these studies consider only slope problems. Few studies have been conducted for lateral support systems. Several codes of practice use the numerical quantity of ‘factor of safety’ to define the suitability of geotechnical design. Whether finite element- or limit equilibrium methods are used, the accurate calculation of the factor of safety remains paramount to quantifying the stability of a geotechnical structure. The aim of this research is to compare limit equilibrium and finite element methods in evaluating the stability, in terms of factor of safety, of soil-nailed and anchored lateral support systems in surface excavations. This was done by using four methods of analysis to calculate the factor of safety. Two traditional limit equilibrium methods were used (trail wedge and method of slices). The newer, finite element strength reduction technique was used. Finally, a hybrid method which combines a finite element analysis with limit equilibrium slip surface analysis was used. These methods of analysis were applied to three different geometries. A uniform slope without any reinforcing was analysed. This was followed by the analysis of an 8.5m soil-nail supported face and a 17m face supported by anchors. A parametric study was conducted for the soil-nailed and anchored excavations. Material properties (friction angle, cohesion etc.), modelling parameters (boundary distances, mesh resolution etc.) and engineering design variables (reinforcement capacity etc.) were varied in order to observe the influence on the factor of safety. It is concluded that limit equilibrium methods, such as a trial wedge method and the method of slices, compare well with each other throughout the analyses. Using a combination of finite elements with a slip surface analysis compares poorly with the other methods. By using the finite element strength reduction technique, an optimised failure mechanism is found. The finite element strength reduction technique compares well with limit equilibrium methods if the following two conditions are met: • The same failure mechanism is evaluated for both methods; and • the capacity of reinforcement is consistently specified in both methods.
Dissertation (MEng)--University of Pretoria, 2017.
Civil Engineering
MEng
Unrestricted

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8

Soliday, Stanley Jr. "Limits of limit equilibrium and finite element techniques applied to cracked debris dams on collapsing foundations". PDXScholar, 1991. https://pdxscholar.library.pdx.edu/open_access_etds/4428.

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Limits of slope stability, limit equilibrium methods, and of the finite element code FEADAM are reached in the application of these methods to the problem of cracked dams constructed on collapsing soils.

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Warren, Sean N. "Limit equilibrium stability analysis utilizing geotechnical data at Mount Baker, Washington /". abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1461537.

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Thesis (M.S.)--University of Nevada, Reno, 2008.
"December 2008." Includes bibliographical references (leaves 109-112). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web. Library also has electronic version on CD-ROM

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10

Ho, Kenneth. "A No-Limit Omaha Hi-Lo Poker Jam/Fold Endgame Equilibrium". Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:24078344.

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Omaha Hi-Lo Poker is a variant of the game of Poker, with more possibilities resulting from having four cards per player and a split Hi and Lo pot, compared to Texas Hold’em Poker. Recently published algorithms, commodity cloud computing, and graphics processor acceleration enable the analysis of more complex games. We use the newly published CFR+ algorithm, OpenCL heterogeneous computing framework, and Amazon Web Services cloud computing to analyse Omaha Hi-Lo Poker. Using these tools, an endgame jam/fold e-Nash Equilibrium is found and a scoring heuristic that approximates this equilibrium strategy is constructed.

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11

Zorrilla, Luc. "Beyond high mutation highrecombination limit in statisticalgenetics". Thesis, KTH, Fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-296875.

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One considers the bi-allelic model in population genetics which describes a population of genomes evolving under the processes of selection, mutation, recombination and drift. A focus is made on the Quasi-Linkage Equilibrium (QLE) phase with recent derivations from Neher and Shraiman, which exists for fast recombinations compared to selection strength and whose dynamics is greatly simplified compared to the general case. Using results in the QLE regime along with Direct Coupling Analysis (DCA) one can infer fitness landscape in a population, in particular epistasis coefficients. Following these ideas, we investigate here in detail a relation between population size, recombination rate and epistasis variance describing where the QLE regime breaks down, from a DCA-inference point of view. In particular, we find that there is no clear variation of the critical recombination rate with population size, but that as expected there is a linear dependence between the standard deviation of total epistasis and that critical recombination rate.
I examensarbetet behandlas modeller i populationsgenetik med två alleler per lokus. Modellerna beskiver hur en mängd genom ändras över tid under inflytande av naturligt urval, mutationer, rekombination och genetisk drift. Fokus ligger på en fas icke-egentlig linkagejämvikt (Quasi Linkage Equilibrium, QLE) med härledningar av Neher och Shraiman. Denna fas finns när rekombination är en snabb process relativt det naturliga urvalet, och förenklar dynamiken avsevärt jämfört med det allmäna fallet. Med användning av resultat som gäller i QLE samt direktkopplingsanalys (Direct Coupling Analysis, DCA) kan man härleda urvalslandskapet i vilket en population befinner sig i, särsklit epistaskoefficienter. Med användning av dessa ideer undersöker vi här i detalj ett samband mellan populationsstorlek, rekombantionshastighet och epistasspridning som beskriver var QLE slutar gälla, från ett DCA- inferens-perspektiv. Vi finner att det inte finns något klart samband mellan den kritiska rekombinationshastigheten och populationsstorleken, men som väntat ett linjärt förhållande mellan epistasvariationen och den kritiska rekombinationshastighete.

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Orellana, Alarcón Rodrigo Ignacio. "Dynamic equilibrium in limit order markets: analysis of depth disclosure and lit fragmentation". Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/140420.

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Magíster en Ciencias de la Ingeniería, Mención Matemáticas Aplicadas
Ingeniero Civil Matemático
Se desarrolla un modelo dinámico a tiempo contínuo que permite el comercio de múltiples mercados financieros interconectados, organizados como limit order markets, en el cual agentes endógenamente toman decisiones óptimas para maximizar el valor esperado de sus ganacias. Los agentes toman sus decisiones considerando incentivos propios, condiciones de mercado, potenciales decisiones de negociación futuras y diferentes estrategias adoptadas por otros agentes. Se concentra el estudio al análisis de divulgación de profundidad y la fragmentación en el contexto de múltiples mercados. Se prueban tres escenarios principales: (i) un único mercado Transparente, (ii) un único mercado Opaco y (iii) un mercado múltiple interconectado entre una bolsa Transparente y una Opaca que comercian el mismo activo. Los resultados principales indican que, en el contexto de un único mercado, la divulgación de profundidad genera una competencia que incrementa el suministro de liquidez y, en consecuencia, reduce el spread, el ruido de mercado e incrementa la profundidad en los precios más competitivos y en el volumen total del libro. Los agentes con una valoración privada absoluta positiva del activo incrementan sus ganancias a costa de los agentes sin valoración privada, al disminuir sus costos de espera y aumentar sus ganancias por transacción. Estos beneficios son amplificados en el contexto de múltiples mercados debido a las restricciones para transar que generan una competencia más agresiva. Se encuentra que hay un flujo de liquidez hacia la componente Transparente debido a los agentes multi mercados proveedores de liquidez, lo cual reduce el spread e incrementa las profundidades. Para mantenerse atractivos, los agentes en la Bolsa Opaca también entran en competencia, lo cual reduce el spread y ruido de mercado en esta bolsa de similar manera. Los agentes multi mercados demandantes de liquidez son los que presentan el mejor rendimiento de todos, principalmente al reducir significativamente los tiempos de sus ejecuciones.
We develop a dynamic model in continuous time to simulate multi markets trading. Traders make endogenously sequential optimal decision to maximize their expected payoffs across different limit order markets, taking into account intrinsic incentives, markets conditions, potential future trading decisions and different strategies adopted by other agents. We focus our study in depth disclosure and lit fragmentation, and test three main scenarios: (i) a single Lit Market, (ii) a single Opaque Market and (iii) Multi Markets interconnected with both Lit and Opaque venues trading a single common asset. Our main results indicate that, in a single market environment, depth disclosure generates a competition that increments liquidity supply and as a consequence, reduces spread, microstructure noise and increases depth at best quotes and total depth of the book. Agents with a positive absolute private valuation of the asset increases their benefits at the expense of agents without a private valuation, by decreasing their waiting costs and increasing their money transfer. These benefits are amplified in a multi market environment due to trading restrictions that generates more aggressive competition. We find a liquidity flow to the Lit venue given by multi market liquidity suppliers, that reduces the spread and increases depths. To stay in competence agents in the Opaque Venue enter the competition as well, reducing spread and microstructure noise in that exchange too. Multi market liquidity demanders with the possibility to trade in both venues have the best performance of all agents, due to a significant reduction in their execution time.

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13

MAGALHAES, MARCELO DE SOUZA. "DESIGN OF ANCHORED RETAINING STRUCTURES USING THE LIMIT EQUILIBRIUM AND THE FINITE ELEMENTO METHODS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=26066@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O dimensionamento de estrutura de contenção flexíveis atirantadas geralmente representa um desafio para os engenheiros civis, devido a complexidade do tema e as severas consequências que uma eventual ruptura pode causar. Visando melhorar a compreensão do comportamento dessas estruturas, bem como o seu dimensionamento, o presente trabalho descreve os mecanismos que governam o comportamento dessas contenções, como por exemplo: o arqueamento das tensões; a redistribuição das tensões; concentração de tensões nas ancoragens, etc. Embora estes mecanismos tenha uma forte influência sobre o comportamento de cortinas atirantadas, eles geralmente não são considerados em projetos, já que na prática brasileira, os dimensionamentos dessas contenções são realizados predominante-mente a partir de métodos de cálculo simples, como por exemplo o cálculo por equilíbrio limite, que não leva em conta esses efeitos. Portanto, no presente trabalho são discutidas as limitações dessa abordagem, e em contrapartida são apresentadas, através de um estudo de caso, os benefícios da aplicação do método dos elementos finitos em análises de escavações.
The design of anchored retaining wall usually represents a challenge for civil engineers, due to the complexity of the issue and the severe consequences that a possible rupture can cause. In order to improve understanding of the behavior of these structures, as well as its design, the present work describes the mechanisms that govern the behavior of these structures, for example: the arching of the stress, the redistribution of stress, concentration of stresses in the anchorages, etc. Although these mechanisms have a strong influence on behavior of the anchored retaining wall, they are usually not considered in design, because the Brazilian practice, the projects of these structures are made predominantly from simple calculation methods, for example by calculating the equilibrium limit, that does not account for these effects. Therefore, in the present work the limitations of this approach are discussed, and on the other hand are presented, via a case study, the benefits of the finite element method applied to the excavation analysis.

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14

Dreyfuss, Miryam Y. (Miryam Yael). "Limit analysis of the Great Hall of Trajan's Markets in Rome using equilibrium methods". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66831.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 49).
This paper studies the Great Hall of Trajan's Markets in Rome using equilibrium analysis to determine the limits of stability of its main vault under gravity loading. In particular, the capacities of three structural components were analyzed individually and as one system to compare the difference in stability limits. Recent studies of the hall that used Finite Element Methods predicted high tensile stresses in the structure, suggesting that there was a danger of further damage and potential collapse under seismic loads. This led to the installation of steel reinforcement systems within the vault and supporting structure. The objective of this thesis is to show that equilibrium methods are able to give an accurate sense of the viable states of the structure, and generally, that equilibrium methods are a more appropriate technique for analyzing highly indeterminate historic masonry structures. The results show that the range of horizontal thrust values increases dramatically when the supporting structures (lateral arch and buttress) are included. Hence, the supporting structures are critical to the stability of the vault under static loading. Furthermore, sliding between the travertine blocks is not a consideration under static loading of the vault.
by Miryam Y. Dreyfuss.
M.Eng.

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15

Firat, Seyhan. "Critical assessment of existing slope stability formulae and application to slope stabilisation". Thesis, University of South Wales, 1998. https://pure.southwales.ac.uk/en/studentthesis/critical-assessment-of-existing-slope-stability-formulae-and-application-to-slope-stabilisation(339ddd93-e0c1-466d-8278-143beca4fb20).html.

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In this research, extensive use has been made of limit equilibrium methods of analysis for studying the stability of slopes. For the determination of the factor of safety (FOS) of slopes, the usual two-step process has been adopted; (a) assuming a slip surface for the soil mass, and (b) using the appropriate limit equilibrium equation(s). Eight wellknown limit equilibrium methods have been programmed to calculate different FOS values. The comparative performance of the various analyses has been carried out successfully using case studies. The innovative use of Gauss quadrature to calculate the FOS values has been shown to reducet he iterative sequencesd ramatically with no loss of accuracy. A visco-plastic flow model has been proposed to estimate lateral forces on piles used for slope stabilisation. The present research data occupies an "in-between" position to the previously reported values, with the variation trend being confirmed satisfactorily in all cases. Slope stabilisation due to the presence of a row of piles has been investigated using two distinct lateral load estimations. These include theories of plastic deformation and the proposed visco-plastic flow which are modelled and implemented in a computer program. Eight well-known methods of slope stability analyses have been adopted and computer coded to re-calculate FOS values for a slope reinforced by a row of piles. A Finite Element computer program has been developed to evaluate the displacement, bending moment and shear force along the pile axis. The pile is analysed at two levels above and below the slip failure surface.

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16

Lam, Yu-wang y 林裕宏. "Limit equilibrium analyses of the cut slope at chainage 23+800 Pos Selim highway Malaysia". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49770445.

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The slope instability occurred in Pos Selim since 1997. Several cut back of the slope had been carried out, however, the instability of the slope was still occurred. In 2006, the head of the slope was moved for 2m. This raises the concern on the failure mechanism of the slope. In this study, slope stability analysis with Limit Equilibrium Method (LEM) was carried out. In view of the interslice shear could play an important role to the overall slope stability, SARMA’s method was adopted in the study. In associate with the ground model develop for the slope stability analysis, analysis of raingauge record and groundwater monitoring record also included in the study.
published_or_final_version
Applied Geosciences
Master
Master of Science

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17

Loehr, John Erik. "Development of a hybrid limit equilibrium-finite element procedure for three-dimensional slope stability analysis /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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18

Burden, Justin Matthewson. "Development and implementation of a limit equilibrium procedure for the three-dimensional analysis of asymmetric landslides". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43891.

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Two-dimensional limit equilibrium types of analysis have been used in engineering practice for decades and are the most commonly adopted analysis technique for assessing the stability of slopes. These methods compute a factor of safety based on a comparison of available to required shear strength along a prescribed failure surface. Forces and static equilibrium conditions are only considered in the plane of movement. However, in reality, all slope failures occur in three-dimensions. Every sliding mass has a finite length and shear forces acting at the lateral extents of the mass contribute to the resistance to movement. Errors introduced by neglecting the three-dimensional character of a slide cannot be overlooked in all cases. Examples include deep narrow excavations, convex/concave slope geometries, slopes that fail by narrow localized failure and structurally controlled failures in rock. Consideration of threedimensional effects may be of particular importance where computed two-dimensional factors of safety are marginal or when back-analyzing slope failures where derived shear strengths should reflect the influence of end effects. This thesis details the development, implementation and evaluation of a general limit equilibrium method of columns procedure suitable for analyzing the three-dimensional stability of asymmetric landslides. The proposed method, termed the three-dimensional asymmetric Spencer method, uses internal force functions to satisfy the equilibrium conditions. Unlike many of its predecessors, the algorithm satisfies force and moment equilibrium in both horizontal directions. The direction of sliding is not assumed, but rather determined explicitly in the analysis. The solution scheme is implemented in the computer program J3D. A moment balancing procedure is developed and used to investigate the effect of enforcing moment equilibrium about a vertical axis of rotation on the analysis results. Analyses completed using J3D are compared with solutions derived using existing limit equilibrium methods and three-dimensional distinct element models for several asymmetric slide examples, including the Kettleman Hills Landfill case history. Preliminary results indicate that the three-dimensional asymmetric Spencer method is well suited for the analysis of general slope stability cases, including asymmetric problems. Application of the proposed moment balancing algorithm may only be suitable for problems involving specialized slope and slip surface geometries.

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19

Fournier, Mathew. "Investigations into the Shear Strength Reduction method using distinct element models". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2492.

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This thesis reports a detailed investigation into the use of the Shear Strength Reduction (SSR) method to determine factor of safety values in discontinuum models using the Universal Distinct Element Code. The SSR method depends on the definition of failure within the model and two different criteria were compared: the numerical unbalanced force definition and a more qualitative displacement-monitoring based method. A parametric study was first undertaken, using a simple homogeneous rock slope, with three different joint networks representing common kinematic states. Lessons learned from this study were then applied to a more complex case history used for validation of the SSR method. The discontinuum models allow for the failure surface to propagate based on constitutive models that better idealize the rockmass than simpler methods such as limit equilibrium (e.g. either method of slices or wedge solutions) and even numerical continuum models (e.g. finite difference, finite element). Joints are explicitly modelled and can exert a range of influences on the SSR result. Simple elasto-plastic models are used for both the intact rock and joint properties. Strain-softening models are also discussed with respect to the SSR method. The results presented highlight several important relationships to consider related to both numerical procedures and numerical input parameters. The case history was modelled similar to how a typical forward analysis would be undertaken: i.e. simple models with complexities added incrementally. The results for this case generally depict a rotational failure mode with a reduced factor of safety due to the presence of joints within the rockmass when compared to a traditional limit equilibrium analysis. Some models with large persistence of steeply dipping joints were able to capture the actual failure surface. Softening models were employed in order to mimic the generation and propagation of joints through the rockmass in a continuum; however, only discontinuum models using explicitly defined joints in the model were able to capture the correct failure surface.

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Engin, Volkan. "Comparison Of Factor Of Safety Obtained From Limit Equilibrium Methods With Strength Reduction Factors In Finite Element Modeling". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614096/index.pdf.

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Designing with Limit Equilibrium Methods involve a factor of safety (FS) in order to maintain the stability and to keep the resisting structure away from limit state on the safe side. Finite Element Program (such as Plaxis) on the other hand, instead of an FS, reduces the shear strength of the soil by introducing a reduction factor that is applied to tan

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21

Franca, Paulo Ricardo Behrens da. "Analysis of slope stability using limit equilibrium and numerical methods with case examples from the Águas Claras Mine, Brazil". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20637.pdf.

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Osores, Tumbalobos Ana Belén. "Optimización del grado de inclinación de taludes provisionales sin sostenimiento en el Conglomerado de lima mediante la técnica de retroanálisis basado en el método de Equilibrio Límite". Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/652234.

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La presente tesis de investigación fue elaborada con la finalidad de contribuir con el estudio de la construcción de rampas de acceso a excavaciones mediante el análisis de los taludes provisionales sin sostenimiento que garanticen la estabilidad global en el Conglomerado de Lima. Las rampas de acceso son estructuras provisionales cuya construcción no se rige bajo normativas o indicaciones establecidas, además no contempla un estudio, se basa en la experiencia del responsable en obra. La ciudad de Lima se emplaza sobre un suelo gravoso el cual contribuye a que sea posible optimizar el grado de inclinación de los taludes provisionales. El alcance de este trabajo consiste en modelar una rampa de acceso en el conglomerado típico de Lima aplicando las sobrecargas existentes de la maquinaria y realizar un análisis de estabilidad global frente a condiciones estáticas y pseudodinámicas. Mediante la técnica de retroanálisis basándose en el método de Equilibrio Límite en Slide se estimarán los parámetros de resistencia mínimos característicos de la grava de Lima, el parámetro de cohesión y ángulo de fricción. A partir de ello se procederá a la optimización de los taludes, evaluando los diferentes grados de inclinación, y se estimarán las deformaciones producidas en los taludes a través del programa Plaxis, basado en Elementos Finitos. Finalmente se exponen las conclusiones obtenidas de la presente tesis de investigación, además de brindar recomendaciones para futuras investigaciones relacionadas a este tema.
This research thesis was developed with the purpose of contributing to the study of the construction of access ramps to building’s excavations by unsupported provisional slopes analysis to guarantee the global stability factor in the Lima Conglomerate. The access ramps are provisional structures whose construction is not governed by norms or established indications, in addition it does not include a study, it is based on the experience of the person responsible for the work. The city of Lima is located on a gravelly ground which helps to optimize the degree of inclination of the provisional slopes. The scope of this work is to model an access ramp in the typical conglomerate of Lima applying the existing machinery overloads and perform an analysis of global stability against static and pseudodynamic conditions. The minimum resistance parameters characteristic of the Lima gravel, the cohesion parameter and friction angle will be estimated using the retro-analysis technique based on the Limit Equilibrium method in Slide. From this, the slopes will be optimized, evaluating the different degrees of inclination, and the deformations produced in the slopes will be estimated through the Plaxis program, based on Finite Elements. Finally, the conclusions obtained from this research thesis are presented, as well as providing recommendations for future research related to this topic.
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23

Hagerfors, Jonas. "Jämförelse av beräkningsprogrammen Novapoint Geosuite Stability och Geoslope SLOPE/W med avseende på släntstabilitet". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-384294.

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This thesis deals with the difference between two calculation programs for slope stability, namely Geoslope SLOPE/W and Novapoint GeoSuite Stability. The purpose of the thesis is to compare the two calculation programs with regard to the analysis of slope stability, as well as the two programs' handling of data. The two calculation programs use different Limit equilibrium methods to calculate safety factor and sliding surfaces for slopes. It can be expected that the result should be similar to one another, as well as the fact that both the calculation programs use different Limit equilibrium methods, but also when large differences in both safety factor and critical sliding surface give unreliable results. The thesis will also address the factors that may lie behind the fact that a possible stability failure should take place in a slope, as it gives an increased understanding of the analyzes that have been done. The work was carried out by modeling slopes with identical geometric relationships and identical material properties in the two calculation programs, a safety factor and a critical sliding surface for the slopes were developed for both programs and then compared with each other.
Föreliggande examensarbete behandlar skillnaden mellan två beräkningsprogram när det kommer till släntstabilitet, nämligen Geoslope SLOPE/W och Novapoint GeoSuite Stability. Syftet med examensarbetet är att jämföra de båda beräkningsprogrammen avseende vid undersökning av släntstabilitet, samt de två programmens hantering av data. De två beräkningsprogrammen använder sig av liknande Limit equilibrium-metoder för att beräkna säkerhetsfaktor samt glidytor för slänter. Man kan förvänta sig att resultatet bör vara varandra likt då dels att de både beräkningsprogrammen använder sig av liknande Limit equilibrium-metoder, men också då stora skillnader i både säkerhetsfaktor och kritisk glidyta ger opålitligt resultat. Examensarbetet kommer även ta upp de faktorer som kan ligga bakom att ett eventuellt brott ska ske i en slänt, då det ger ökad förståelse för de analyser som gjorts. Arbetet utfördes genom att slänter med identiska geometriska relationer samt identiska materialegenskaper modellerades i de båda beräkningsprogrammen, en säkerhetsfaktor samt kritisk glidyta för slänterna togs fram för båda programmen och jämfördes sedan med varandra.

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24

Ong, Chin Chai. "Behaviour and analysis of embedded cantilever wall on a slope". University of Western Australia. School of Civil and Resource Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0076.

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[Truncated abstract] The feasibility of using interlocked light gauge sheet piles to form a deep cross-sectional wall embedded in a residual slope or with a berm support is explored. This thesis compares the performance of a large section modulus sheet pile wall as an alternative to a concrete diaphragm wall, acting as an embedded cantilever wall on a slope (ECWS) by means of experimental centrifuge tests, numerical models and analytical methods. Abaqus (Hibbitt, Karlsson and Sorensen Inc, 1997) was used to conduct extensive numerical trials on the structural performance of the sheet pile wall model prior to the actual physical testing. The Abaqus results showed that the integrity of the interlock and reduced modulus action (RMA) due to slippage along the interlocked joint did not cause premature buckling of the thin wall even at the ultimate load. Further, a comparative study using centrifuge tests on 1:30 scaled models and Plaxis analysis demonstrated that under the worst condition with high water table, the rigid sheet pile wall of 1.32 m cross-sectional width carried a higher ultimate surcharge load with a much lower top of wall deflection, compared to a more flexible 0.6 m thick cracked concrete diaphragm wall. The analysis of the wall/soil/slope interactions for an ECWS involves many inter-dependent variables in addition to the complications of considering an adjacent slope or a berm support. It is difficult for existing analytical approaches to take all these factors into account, and some form of numerical analysis, calibrated through field data and results from centrifuge model tests is necessary. From the observations of the centrifuge tests and finite element analysis, major assumptions about the failure of a stiff ECWS in a rotational mode were deduced and adopted in the proposed limiting equilibrium method (Leq). The plane strain Leq ECWS Abstract ii analysis is based on the framework of minimum upper bound limiting equilibrium with planar failure planes and a Mohr-Coulomb soil model. As compared to the traditional limit equilibrium analysis, the Leq method is a fully coupled analysis using the shear strength reduction technique (SSR). New formulations are proposed for the development of horizontal active and passive pressure distributions based on the experimental and FE models. The proposed active pressure profile used is derived by combining the Coulomb and Krey method, and empirically back-figured to curve-fit the centrifuge tests by Morris (2005). The proposed passive pressure profile of a rigid rotational wall in failure is adjusted to allow for an adjacent slope or berm support through a presumed elasto-plastic deformation instead of a linear rigid translation of the passive wedge. ... A parametric study was later undertaken using the Leq method to develop a series of non-dimensionalised graphs to study and draw summarised conclusions on the behaviour of the ECWS. The final conclusions on the comparative study of the centrifuge tests, Plaxis and Leq analyses demonstrated that the alternative light gauge steel sheet pile performed very well as an ECWS. A key factor in the performance of the sheet pile wall was attributed to the large 1.32 m cross-sectional width of the interlocked sections. This provided high bending stiffness and high moment stability from shear stresses acting on the back and front faces of the wall.

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25

Antocheviz, Rafael Bugs. "Metodologia para determinação do procedimento a ser utilizado em uma análise de estabilidade de taludes : ruptura circular". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/184854.

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Análises de estabilidade de taludes, em mineração, são uma das atividades mais importantes do processo de obtenção de um bem mineral. Assegurar a estabilidade das escavações e a segurança do empreendimento são vitais para o processo de extração e, para tanto, a escolha da forma de análise (2D, quasi-tridimensional ou 3D) ou do método (equilíbrio limite ou análise numérica) mais propício para esse tipo de estudo é de suma importância. Muitas vezes o engenheiro responsável acaba baseando sua escolha na familiaridade com determinada metodologia ou na praticidade de determinado programa, em detrimento a fatores técnicos e de relevância para o estudo. Dessa forma, visando preencher tal lacuna existente atualmente e facilitar a escolha da melhor metodologia a ser utilizada, o presente estudo reúne os principais métodos conhecidos, suas vantagens e desvantagens e, assim, propõem uma metodologia para que essa escolha seja baseada em parâmetros técnicos relevantes. A metodologia proposta é, de certa forma, restritiva na escolha dos procedimentos que serão considerados, uma vez que, buscou-se utilizar métodos que tenham sua aplicabilidade comprovada, que possuam vantagens consideráveis sobre outros métodos e que sejam rigorosos, ou seja, satisfaçam todas as condições de equilíbrio (forças e momentos). Para corroborar com a metodologia proposta, quatro situações práticas diferentes foram apresentadas, demonstrando a aplicabilidade da metodologia.
Analysis of slope stability in mining is one of the most important activities of the process of obtaining a mineral resources. Ensuring the excavation stability and the safety of the project are vital to the extraction process. The choice of the form of analysis (2D, quasi-threedimensional or 3D) or of the method (limit equilibrium or numerical analysis) more suitable for this type of study is of paramount importance since, the responsible engineer often end up basing the analysis on familiarity with a particular methodology or on the availability of a particular program, to the detriment of technical factors and relevance to the study. Thus, in order to fill this existing gap and facilitate the selection of the best methodology to be used, the present study brings together the main known methods, their advantages and disadvantages and, therefore, presents a methodology for such a choice to be based on relevant technical parameters. The proposed methodology is somewhat restrictive in the choice of procedures that will be considered, since it has been tried to use methods that have proven applicability, that have considerable advantages over other methods and that are rigorous, satisfying all equilibrium conditions (forces and moments). In order to corroborate the proposed methodology, four different practical situations were presented, demonstrating the applicability of the methodology.

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26

Albataineh, Nermeen. "SLOPE STABILITY ANALYSIS USING 2D AND 3D METHODS". University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1153719372.

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Poruba, Michal. "Návrh sanace sesuvu". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227466.

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Main goal of thesis entitled "Landslide remediation design" is - based on acquired knowledge and submitted documents about the problematic of landslides - to determine the causes of the landslides on II. class road between villages Koryčany and Jestřabice and to propose optimal redevelopment.

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28

Nogueira, Renan Teixeira. "Simulação numérica e equilíbrio limite aplicado a retroanálise de taludes em mineração de carvão". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/152747.

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A pesquisa voltada para a retroanálise de taludes de mineração está se tornando cada vez mais importante. As dimensões das atuais cavas de mineração visam sempre obter a melhor relação entre custo, benefício e segurança. Isso exige que por vezes o trabalho ocorra próximo destes limites. Neste trabalho o estudo de retroanálise consiste em um talude misto composto por aluvião e rocha em uma mineração de carvão localizada no município de Arroio dos Ratos, RS. O objetivo foi realizar um estudo de retroanálise onde se utilizou dois métodos de análise método dos Elementos Finitos (MEF) e o método do Equilíbrio Limite (EL). A metodologia adotada foi dividida em três fases: uma etapa de campo, para coleta do material e dados geométricos do talude, uma etapa de laboratório para caracterizar todo o material e a última etapa computacional onde foram gerados os modelos e simulações numéricas através dos softwares comerciais da empresa RocScience, sendo eles o SLIDE e o RS2. Os resultados encontrados mostraram que a porção do talude composta por aluvião apresentava seis camadas intercaladas de areias bem graduadas e argilas de média a alta plasticidade. Em relação as simulações, observou uma diferença entre o MEF e EL devido ao grande número de camadas presentes no talude e a interação entre elas. Foram criados quatro diferentes cenários para observar o comportamento do talude, com presença e ausência de água. O MEF mostrou uma superfície de ruptura próxima a encontrada porem com a presença de água o Fator de Segurança (FS) sofreu uma grande depreciação. O EL considerou uma superfície de ruptura satisfatória, nas simulações com presença de água FS sofreu uma depreciação mínima mesmo com máxima saturação de água no talude. Apesar das diferenças ambos os métodos são confiáveis mas devem ser usados de forma adequado ao tipo de problema existente. Situações mais simples e com taludes mais homogêneos o EL trona-se mais indicado, para problemas de maior complexidades e interações entre camadas o MEF se mostrou satisfatório e com boa resposta. O resultados através do MEF se aproximaram mais da situação real encontrada em campo.
A research focus on retro analysis on mine slopes is becoming increasingly important. The dimensions of current mining caves aim to always obtain the best cost benefit ratio as well as the highest safety level. This demands that the work sometimes is done within these limits. In this paper the study of retro analysis is made up of a mixed slope composed of alluvial and rocks, in a coal mine in Arroio dos Ratos, RS. The goal was to carry out a retro analysis study using two analysis methods: The Finite Element Method (FEM) and Limit Equilibrium analysis (LE). The methodology adopted was split into three phases: a field stage for the sample collection and slopes geometric , a laboratory stage to classify all the material and a final computacional stage were model and numerical simulations were created by way of commercial software, Slide and RS2, by RocScience. The results showed that the portion of the slope composed of alluvium had six layers interspersed with well graded sands and high plasticity clays. The simulations observed a difference between the FEM and LE due to the number of layers present in the slope and the interaction among them. Four different scenarios were created in order to observe the behavior of the slope. The FEM presents surface failure similar to one found in the field. The LE always takes into consideration the overall critical surface which is not observed in the field, it also show high security factor levels above one 1.3 that does not reflect a real situation since the slope is collapsed. In spike of the differences, both methods are reliable but they must be used according to the existing problems. For simpler situations with homogeneous slopes LE is recommended while move complex problems and interactions among lawyers calls for FEM.

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Arikan, Asli Huriye. "Assessment Of Slope Stability For A Segment (km: 25+600-26+000) Of Antalya-korkuteli Highway". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612265/index.pdf.

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The cut slopes at a segment between Km 25+600 and 26+000 of the Antalya-Burdur Breakaway-Korkuteli State Road to be newly constructed have slope instability problems due to the existence of highly jointed limestone. The purpose of this study is to investigate the engineering geological properties of the units exposed at three cut slopes, to assess stability of the cut slopes, and to recommend remedial measures for the problematic sections. In this respect, both field and laboratory studies have been carried out. The limestone exposed at the cut slopes are beige to gray, fine grained, fossiliferous, and highly jointed. It has two joint sets and a bedding plane as main discontinuities. The kinematic analysis indicates that planar failure is expected at Km: 25+900. Limit equilibrium analysis show that the cut slopes with bench have no slope instability problems except rockfalls which endanger the traffic safety. In this thesis it is recommended to covering the cut slope with wire mesh and fibre reinforced shotcrete

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Giacon, Junior Admir José. "Análise probabilística da estabilidade de taludes via teoria da confiabilidade". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/152916.

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Devido às consequências negativas associadas à ruptura e deslizamentos de taludes, a análise de estabilidade desses assume uma parte primordial na área da engenharia geotécnica. A maioria dessas análises é realizada de maneira determinística, não incorporando as incertezas inerentes ao sistema. A constatação dessas incertezas em projetos de taludes associa-se a previsão de uma probabilidade de falha no desempenho de taludes quanto à segurança. Nesse contexto, esta dissertação busca avaliar a segurança de taludes através de uma abordagem probabilística, simulando taludes com geometrias e solos variados, verificando ainda a influência da elevação da posição do nível d´água. Para essa finalidade foram realizadas análises probabilísticas utilizando First Order Reliability Method (FORM) com base nos métodos de Equilíbrio Limite, através dos programas computacionais acadêmicos RASS (análises determinísticas) e RELgen (análises probabilísticas). Com base nos resultados, verificou-se que as superfícies críticas obtidas pelos métodos determinísticos podem não coincidir com as superfícies que apresentam a maior probabilidade de falha. Isto é verificado ainda na análise de inclinação da superfície do talude, em que inclinações apresentando fatores de segurança admissíveis, apresentaram probabilidades de falha não aceitáveis. Estas divergências são atribuídas às incertezas inerentes ao sistema. Sendo assim, as análises de estabilidade de talude baseadas apenas nos resultados de análises determinísticas não apresentam todas as variáveis presentes no contexto do projeto. Por fim, através dos resultados obtidos nesta pesquisa é possível inferir que a adoção da análise probabilística em projeto de taludes auxilia de uma forma consistente a avaliação da segurança dos taludes, contribuindo de maneira satisfatória na prática de projetos de engenharia geotécnica.
Due to the negative consequences associated with slope rupture and landslides, the stability analysis of these slopes plays an important role in geotechnical engineering. Most of these analyzes are carried out in a deterministic manner, not incorporating the uncertainties inherent to the system. The observation of these uncertainties in slope projects is associated with the forecast of a probability of failure in slope performance in terms of safety. In this context, this paper present research seeks to evaluate slope safety in a probabilistic manner, simulating slopes with varied geometries and soils, also verifying the influence of elevation of the water level position. For this purpose, were performed probabilistic analyzes using First Order Reliability Method (FORM), based on the Limit Equilibrium methods, RASS (deterministic analysis) and RELgen (probabilistic analyzes). Based on the results, it was found that the critical surfaces obtained by the deterministic methods may not coincide with the highest most probability surfaces to fail. This is still verified in surface slope analysis, where inclinations with acceptable safety factors presented probabilities of failure unacceptable. These divergences are attributed to the uncertainties inherent in the system. Therefore, slope stability analyzes based only on the results of deterministic analyzes do not present all the variables present in the project context. Finally, through the results obtained in this research it is possible to infer that the adoption of probabilistic analysis in slope design assists in a consistent way the assessment of slope safety, contributing in a satisfactory way in the practice of geotechnical engineering projects.

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31

Höglund, Andreas. "Electronic Structure Calculations of Point Defects in Semiconductors". Doctoral thesis, Uppsala universitet, Fysiska institutionen, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7926.

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In this thesis point defects in semiconductors are studied by electronic structure calculations. Results are presented for the stability and equilibrium concentrations of native defects in GaP, InP, InAs, and InSb, for the entire range of doping conditions and stoichiometry. The native defects are also studied on the (110) surfaces of InP, InAs, and InSb. Comparing the relative stability at the surface and in the bulk, it is concluded that the defects have a tendency to migrate to the surface. It is found that the cation vacancy is not stable, but decomposes into an anion antisite-anion vacancy complex. The surface charge accumulation in InAs is explained by complementary intrinsic doping by native defects and extrinsic doping by residual hydrogen. A technical investigation of the supercell treatment of defects is performed, testing existing correction schemes and suggesting a more reliable alternative. It is shown that the defect level of [2VCu-IIICu] in the solarcell-material CuIn1-xGaxSe2 leads to a smaller band gap of the ordered defect γ-phase, which possibly explains why the maximal efficiency for CuIn1-xGaxSe2 has been found for x=0.3 and not for x=0.6, as expected from the band gap of the α-phase. It is found that Zn diffuses via the kick-out mechanism in InP and GaP with activation energies of 1.60 eV and 2.49 eV, respectively. Explanations are found for the tendency of Zn to accumulate at pn-junctions in InP and to why a relatively low fraction of Zn is found on substitutional sites in InP. Finally, it is shown that the equilibrium solubility of dopants in semiconductors can be increased significantly by strategic alloying. This is shown to be due to the local stress in the material, and the solubility in an alloy can in fact be much higher than in either of the constituting elements. The equilibrium solubility of Zn in Ga0.9In0.1P is for example five orders of magnitude larger than in GaP or InP.

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Mejía, José Luis Leiva. "Estabilidade de talude com efeito sísmico a partir dos métodos de equilíbrio limite e de elementos finitos". Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8826.

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A Costa Peruana apresenta alta atividade sísmica, tornando imprescindível a execução de análises de estabilidade que considerem os eventos sísmicos. Com o desenvolvimento de novas ferramentas numéricas, a análise dinâmica está se tornando cada vez mais importante e usual na fase de projeto, não se justificando mais a execução de análises estáticas em locais tão vulneráveis a sismos. A presente dissertação tem como objetivo realizar a análise da estabilidade dos Penhascos de Lima, Peru, considerando quatro taludes distintos, em uma região bastante afetada por abalos sísmicos. As análises foram executadas pelos métodos de equilíbrio limite, elementos finitos e pseudo-estático, buscando-se uma comparação entre os diferentes métodos. O trabalho apresenta uma descrição completa dos taludes em estudo, uma avaliação da condição sismológica da região e finalmente a estabilidade dos Penhascos de Lima, fazendo uso dos programas computacionais Slide (método do equilíbrio limite) e Plaxis (método dos elementos finitos) em 2D. Os resultados mostraram que os três métodos adotados forneceram fatores de segurança compatíveis, principalmente quando se considera perfis menos estratificados. Para perfis homogêneos, as diferenças obtidas foram da ordem de 0,5 a 1,0 %. As análises ressaltaram a importância de considerar a condição dinâmica, e mostraram-se bastante sensíveis aos valores de carga sísmica adotado.
The Peruvian coast has high seismic activity, making essential the implementation of stability analyzes that consider the seismic events. With the development of new numerical tools, dynamic analysis is becoming increasingly important and usual in the design phase is not justified over the execution of static analysis in places as vulnerable to earthquakes. This thesis aims to conduct the analysis of the stability of the cliffs of Lima, Peru, considering for different slopes, in a region highly affected by earthquakes. The analyzes were performed by equilibrium methods limit finite elements and pseudo-static, seeking a comparison between the different methods. The dissertation presents a complete description of the slopes in the study, an evaluation of the seismic condition of the region and finally the stability of Lima cliffs, making use of computer programs Slide (limit equilibrium method) and Plaxis (finite element method). The results showed that all three methods provided adopted gave safety factors, especially when considering less laminated profiles. For homogeneous profiles, obtained differences were of the order of 1.0 at 0.5%. The analysis highlighted the importance of considering the dynamic condition, and were quite sensitive to seismic load values adopted.

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Letizia, Viviana. "Modèles microscopiques pour la loi de Fourier". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLED038/document.

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Cette thèse est consacrée à l’étude des modèles microscopiques pour la dérivation de la conduction de la chaleur. Démontrer rigoureusement une équation diffusive macroscopique à partir d’une description microscopique du système est à aujourd’hui encore un problème ouvert. On étudie un système décrit par l’équation de Schrödinger linéaire discrète (DLS) en dim 1, perturbé par une dynamique stochastique conservative. On peut montrer que le système a une limite hydrodynamique donnée par la solution de l’équation de la chaleur. Quand le système est rattaché aux bords à deux réservoirs de Langevin à deux différents potentiels chimiques, on peut montrer que l’état stationnaire, dans la limite vers l'infinie, satisfait la loi de Fourier. On étudie une chaine des oscillateurs anharmonique immergée en un réservoir de chaleur avec un gradient de température. On exerce une tension, variable dans le temps, à une des deux extrémités de la chaine, et l’autre reste fixe. On montre que sous un changement d’échelle diffusive dans l’espace et dans le temps, la distribution d’étirement de la chaine évolue selon un équation diffusive non-linéaire. On développe des estimations qui reposent sur l’hypocoercitivité entropique. La limite macroscopique peut être utilisée pour modéliser les transformations thermodynamique isothermiques entre états stationnaire de non-équilibre
The object of research of this thesis is the derivation of heat equation from the underlying microscopic dynamics of the system. Two main models have been studied: a microscopic system described by the discrete Schrödinger equation and an anharmonic chain of oscillators in presence of a gradient of temperature. The first model considered is the one-dimensional discrete linear Schrödinger (DLS) equation perturbed by a conservative stochastic dynamics, that changes the phase of each particles, conserving the total norm (or number of particles). The resulting total dynamics is a degenerate hypoelliptic diffusion with a smooth stationary state. It has been shown that the system has a hydrodynamical limit given by the solution of the heat equation. When it is coupled at the boundaries to two Langevin thermostats at two different chemical potentials, it has been proven that the stationary state, in the limit to infinity, satisfies the Fourier’s law. The second model considered is a chain of anharmonic oscillators immersed in a heat bath with a temperature gradient and a time varying tension applied to one end of the chain while the other side is fixed to a point. We prove that under diffusive space-time rescaling the volume strain distribution of the chain evolves following a non-linear diffusive equation. The stationary states of the dynamics are of non-equilibrium and have a positive entropy production, so the classical relative entropy methods cannot be used. We develop new estimates based on entropic hypocoercivity, that allows to control the distribution of the positions configurations of the chain. The macroscopic limit can be used to model isothermal thermodynamic transformations between non-equilibrium stationary states. CEMRACS project on simulating Rayleigh- Taylor and Richtmyer-Meshkov turbulent mixing zones with a probability density function method at last

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34

Oge, Ibrahim Ferid. "Slope Stability Analysis And Design In Elbistan-collolar Open Cast Mine". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609939/index.pdf.

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Slope stability is an important aspect of geotechnical engineering. Input parameters for the analysis are the governing factors and they must be determined accurately and precisely. Field investigations, laboratory testing and back analyses are vital instruments for the input parameters. This study presents the results of slope stability analysis for the soil slopes at Elbistan-Ç
ö
llolar lignite mine. After executing the drilling programme, samples taken from the drilling work, delivered to soil mechanics laboratory for testing. The basic input parameters, namely cohesion and friction angle determined at soil mechanics laboratory were compared to the parameters obtained from back analysis of a large scale slope failure. Input parameters for the analysis are determined by this way. After determining the input parameters, slope stability analyses were carried out both for the permanent and temporary slopes in AfSin-Elbistan lignite basin, Ç
ö
llolar sector. The effect of ground water on the stability of slopes was investigated in detail and maximum safe slope angles were determined for different water levels. For limit equilibrium analysis, Rocscience SLIDE software, for finite difference analysis in 3-D, Itasca FLAC3D was used. In the limit equilibrium analyses both circular and composite failures were considered. Shear strength reduction method is used for the finite difference method. The results between limit equilibrium and 3-D finite difference methods were compared. When the failure surfaces obtained from the finite difference analyses were imposed to limit equilibrium analysis, computations are resulted in lower factor of safety values for limit equilibrium analysis.

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35

Erignoux, Clément. "Limite hydrodynamique pour un dynamique sur réseau de particules actives". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX011/document.

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L'étude des dynamiques collectives, observables chez de nombreuses espèces animales, a motivé dans les dernières décennies un champ de recherche actif et transdisciplinaire. De tels comportements sont souvent modélisés par de la matière active, c'est-à-dire par des modèles dans lesquels chaque individu est caractérisé par une vitesse propre qui tend à s'aligner avec celle de ses voisins.Dans un modèle fondateur proposé par Vicsek et al., ainsi que dans de nombreux modèles de matière active liés à ce dernier, une transition de phase entre un comportement chaotique à forte température, et un comportement global et cohérent à faible température, a été observée. De nombreuses preuves numériques de telles transitions de phase ont été obtenues dans le cadre des dynamiques collectives. D'un point de vue mathématique, toutefois, ces systèmes actifs sont encore mal compris. Plusieurs résultats ont été obtenus récemment sous une approximation de champ moyen, mais il n'y a encore à ce jour que peu d'études mathématiques de modèles actifs faisant intervenir des interactions purement microscopiques.Dans ce manuscrit, nous décrivons un système de particules actives sur réseau interagissant localement pour aligner leurs vitesses. L'objet de cette thèse est l'obtention rigoureuse, à l'aide du formalisme des limites hydrodynamiques pour les gaz sur réseau, de la limite macroscopique de ce système hors-équilibre, qui pose de nombreuses difficultés techniques et théoriques
Collective dynamics can be observed among many animal species, and have given rise in the last decades to an active and interdisciplinary field of study. Such behaviors are usually modeled by active matter, in which each individual is self-driven and tends to align its velocity with that of its neighbors.In a classical model introduced by Vicsek & al., as well as in numerous related active matter models, a phase transition between chaotic behavior at high temperature and global order at low temperature can be observed. Even though ample evidence of these phase transitions has been obtained for collective dynamics, from a mathematical standpoint, such active systems are not fully understood yet. Some progress has been achieved in the recent years under an assumption of mean-field interactions, however to this day, few rigorous results have been obtained for models involving purely local interactions.In this manuscript, we describe a lattice active particle system interacting locally to align their velocities. This thesis aims at rigorously obtaining, using the formalism developed for hydrodynamic limits of lattice gases, the scaling limit of this out-of-equilibrium system, for which numerous technical and theoretical difficulties arise

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36

Öhrn, Angelica. "Neutron Scattering at 96 MeV". Doctoral thesis, Uppsala universitet, Tillämpad kärnfysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8425.

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Data on elastic scattering of 96 MeV neutrons from 56Fe, 89Y and 208Pb in the angular interval 10-70° are presented. The previously published data on 208Pb have been extended, as a new method has been developed to obtain additional information at the most forward angles. The results are compared with phenomenological and microscopic optical potentials. The theory predictions are in general in good agreement with the experimental data. A study of the deviation of the zero-degree cross section from Wick's limit has been performed. The data on 208Pb are in agreement with Wick's limit, while those on lighter nuclei overshoot the limit significantly. A novel analysis method has been developed to obtain the inelastic neutron emission cross sections from the existing 56Fe data. The method is based on folding a trial spectrum with the response of the detector setup. The data cover the angular interval 26-65° and an excitation energy range of 0-45 MeV, ranges hitherto not studied. The results are compared with nuclear model predictions and found to be in good agreement with the experimental data.

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37

Júnior, Carlos Alberto Ribeiro. "Análise numérica de escorregamento em encostas". Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5526.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O perfeito entendimento de deslizamentos de terra tem sido objeto de grande interesse na engenharia geotécnica há muitos anos. Encostas naturais representam um desafio constante para os engenheiros, mais do que os taludes artificiais. Não é incomum que os escorregamentos causam perdas de vidas humanas e também danos materiais. As informações obtidas a partir de retro-análise de casos históricos, têm servido como uma ferramenta valiosa para a compreensão da estabilidade de taludes. Vale a pena notar que o primeiro método de cálculo de estabilidade de taludes, usando divisão de fatia, foi desenvolvido após um acidente na Noruega. Métodos de estabilidade por Equilíbrio Limite, desenvolvidos no século passado são atualmente utilizados na prática da engenharia. Apesar de suas deficiências, eles provaram ser confiáveis na determinação do Fator de Segurança. A geometria 2D e a abordagem completa da condição saturada são provavelmente as questões mais relevantes dos métodos atuais. A condição do solo não saturado está geralmente presente em taludes naturais e os métodos ignoram a influência da sucção do solo sobre a estabilidade do talude. O desenvolvimento de computadores no meio do século passado, tornaram os cálculos Equilíbrio Limite fáceis de serem executados. Por outro lado, eles não podem explicar a natureza do problema ou prever o comportamento do solo antes da ruptura. A década de 1960 marcou o início do desenvolvimento de programas de computador baseados em métodos numéricos que, entre outros, destaca-se, em geotecnia, a aplicação dos métodos de Elementos Finitos (FEM). Este método é ideal para muitos fins, uma vez que permite a simulação da sequência de construção e também a incorporação de diferentes modelos constitutivos. Este trabalho mostra a influência da sucção sobre a estabilidade de encostas naturais. Uma retroanálise de um escorregamento no Morro dos Cabritos, no Rio de Janeiro, foi feita através de um programa de análise de tensão (Plaxis 2D). Os resultados foram comparados com o FS obtido por programa de Equilíbrio Limite (Slide v5). O efeito de sucção do solo foi incorporada nas análises, através de sua influência sobre os parâmetros de resistência do solo e por diferentes possibilidades de infiltração de água na encosta. Este caso histórico foi estudado anteriormente por Gerscovich (1994), que na época, fez analise de fluxo e estabilidade utilizando um abordagem de Equilíbrio Limite 3D. Os resultados mostraram boa concordância entre a análise de Elementos Finitos e a simulação de Equilíbrio Limite, sem a presença de nível de água. Os resultados confirmaram que foi necessário haver pressões positivas para explicar a ruptura do talude.

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38

Cubides, Victor Andres Vargas. "Sobre existência de estados de equilíbrio e limite em temperatura zero para shifts de Markov topologicamente mixing". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-25112016-214355/.

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O objetivo desta tese é demonstrar que para um subshift de Markov topologicamente transitivo com alfabeto enumerável e um potencial ƒ com pressão de Gurevic finita e variação limitada (ƒ) < ∞, existe um único estado de equilíbrio µtƒ para cada t > 1, e a família (µtƒ)t>1 tem um ponto de acumulação quando t > ∞. Além disso se também supomos que o ƒ é um potencial de Markov, demonstramos que a família de estados de equilíbrio (µtƒ)t>1 converge quando t > ∞. Finalmente demonstramos a continuidade em ∞ da entropia com respeito ao parâmetro t. Estes resultados não dependem da hipótese de existência de medidas de Gibbs.
The aim of this thesis is to prove that for a topologically transitive Markov subshift with countable alphabet and a summable potential ƒ with finite topological pressure Gurevic and bounded variation (ƒ) < ∞, there exists an equilibrium state µtƒ tf for each t > 1 and the family of equilibrium states (µtƒ)t>1 associated to each potential tf has an accumulation point at t > ∞. Moreover if we also assume that ƒ is a Markov potential we prove that the equilibrium states family (µtƒ)t>1 converges when t > ∞. Finally we prove the continuity at ∞ of the entropy with respect to the parameter t. These results do not depend on assuming the existence of Gibbs measures.

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39

Cebiroglu, Gökhan. "Three essays on hidden liquidity in financial markets". Doctoral thesis, Humboldt-Universität zu Berlin, Wirtschaftswissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/16964.

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An den Handelsbörsen der Welt, hat der Anteil unsichtbarer Luidität in den letzten Jahren dramatisch zugenommen. Obwohl dieser Trend zunehmend in den Fokus regulatorischer Debatten und akademischer Dikussionen rückt, sind sich Forscher und die Aufsichtsbehörden über die Implikationen und entsprechende regulatorische Maßnahmen uneins. In der vorliegenden Arbeit, werden die damit verbundenen Fragestellungen in drei separaten Kapiteln theoretisch und empirisch untersucht. Mit Hilfe eines speziellen NASDAQ Datensatzes, werden in Kapitel 1 die Marktfaktoren, die unsichtbaren Liquidität begünstigen sowie den Einfluß, den unsichtbare Liquidät auf Märkte ausübt, empirisch ausgewertet. Wir zeigen, daß die Querschnittsvariation unsichtbarer Liquidität entlang des Aktienuniversums in einem hohen Maße durch sichtbare Markteigenschaften erklärt wird. Wir zeigen, daß unsichtbare Order gegenüber sichtbaren Ordern signifikant stärkere Preisfluktuationen hervorrufen. Unsere Resultate geben Grund zu der Annahme, daß Märkte mit hoher unsichtbarer Liquidät volatiler sind und höheren Marktreibungen ausgesetzt sind. In Kapitel 2 entwickeln wir ein strukturelles Handelsmodell und untersuchen die optimale Handelsstrategie mit unsichtbaren Ordern. In diesem Rahmen leiten wir für verschiedene Marktspezifikationen explizite Charakterisierungen der sogenannten optimalen Exposure-Größe her. Unter anderem zeigen wir, daß der Einsatz unsichtbarer Order Transaktionskosten signifikant reduzieren kann. In Kapitel 3 entwickeln wir ein dynamisches, Gleichgewichtsmodell in einem Limitorderbuchmarkt. Innerhalb dieses theoretischen Rahmens können die empirischen Beobachtungen des ersten un zweiten Kapitels rationalisiert werden. Insbesondere zeigen wir daß große versteckte Order Marktineffizienzen hervorrufen und Preisfluktuationen verstärken, indem sie die Koordination zwischen Angebots- und Nachfrageseite schwächen können.
In recent years, the proliferation of hidden liquidity in financial markets has increased dramatically and shifted to the center regulatory debates and market micro-structure panels. Yet investors, scientists and policy makers are at odds about its implications and the adequate regulatory responses. This thesis addresses these issues in three separate chapters on both empirical and theoretical grounds. Chapter 1 provides an empirical investigation of the determinants and impact of hidden order submissions. We report that the cross-sectional variation of hidden liquidity is well explained by observable market characteristics. Second, our results suggest that the hidden orders generate substantial price reactions. Our results suggests that hidden liquidity increases market volatility and trading frictions. Chapter 2 proposes a structural trading model. We investigate trader’s optimal trading strategies with respect to order-exposure in limit order book markets. The optimal exposure size marks a trade-off between costs and benefits of exposure. Our model provides explicit characterizations of the optimal exposure size for various market specifications. Model parameters and exposure strategies are estimated through high-frequency order book data. Our results suggest that hidden orders can substantially enhance trade performance. Chapter 3 develops a dynamic equilibrium model with a public primary market and an off-exchange trading mechanism. Our theory correctly predicts the key findings of chapter one and two. For instance, we show that large hidden orders cause excess returns and increase market volatility and correctly predict the role of the observable market characteristics in the origination of hidden liquidity.

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40

Nguyen, Anh Tuan. "Influence des incertitudes géométriques et de la méthode de modélisation dans l'analyse de stabilité des talus rocheux : application aux mines à ciel ouvert". Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0296/document.

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La stabilité des exploitations à ciel ouvert (mines ou carrières) excavées dans des massifs rocheux dépend de leur géométrie, des caractéristiques géométriques de la fracturation (orientation et espacement) du massif et des caractéristiques mécaniques du massif et des discontinuités. L'évaluation du risque d'instabilité rocheuse dépend de la quantité et la qualité des informations disponibles sur le massif rocheux et des méthodes d'analyse mises en œuvre pour évaluer le comportement mécanique de l'assemblage de blocs rocheux. Différents sites de talus naturels, d'excavation routière et de carrières et mines à ciel ouvert présentés dans le mémoire montrent que les informations connues peuvent beaucoup varier d'un site à l'autre. Les étapes de collecte et de synthèse des données, puis de modélisation afin d'analyser la stabilité d'une pente rocheuse conduisent à des incertitudes. Le mémoire traite plus particulièrement de l'influence des incertitudes géométriques et différentes méthodes de regroupement des fractures en familles sont explorées. La combinaison du travail proposé par différents auteurs conduit à une nouvelle méthode nommée PSMY. Cette méthode ainsi que la méthode spectrale ont été programmées sous l'environnement Mathematica et les résultats sont comparés à des regroupements "manuels" réalisé avec le logiciel DIPS. Les méthodes de regroupement sont présentées selon le pourcentage d'orientations classé par la méthode. L’orientation et l’espacement des familles de fractures sont ajustées à des lois statistiques. Les paramètres statistiques sont comparés en fonction de la méthode regroupement. Ces paramètres influencent la construction d'un modèle géométrique du massif rocheux appelé DFN (Discrete Fracture Network). L'influence des regroupements sur l'analyse de stabilité est étudiée à partir de modélisation stochastiques à l'équilibre limite utilisant les logiciels SWEDGE et RESOBLOK. Ces logiciels ne prennent pas en compte les mêmes incertitudes et en sortie ils fournissent des indicateurs de stabilité différents. Une analyse de sensibilité des indicateurs (nombre de blocs instables, volume moyen du bloc instable, volume total instable) aux méthodes de regroupement et aux orientations de talus est réalisée. Une analyse de variance permet de préciser l'influence de ces deux facteurs. Une évaluation de l’état de stabilité global du massif, en fonction de la cohésion et de l'angle de frottement est proposée. L'influence de la méthode de modélisation est évoquée en comparant des calculs tridimensionnels à l'équilibre limite et des modélisations bidimensionnel et tridimensionnels en éléments discrets rigides ou déformables. Un couplage entre le logiciel RESOBLOK (équilibre limite) et LMGC90 (éléments discrets) permet de comparer les analyses pour une même géométrie. Pour le cas de la déviation d'Ax-les-Thermes et certaines configurations géométriques instables l’influence des paramètres de modèles sur stabilité du talus est testée. Plusieurs variantes sont comparées. La simulation d’une excavation en 3D multi phases est réalisée et l’indice de mobilisation est étudié pour comparer les divers types de contacts dans LMGC90 par rapport à l’éventuel glissement des blocs dans les étapes successives
The stability of open-cast operations (mines or quarries), excavated in rock mass depends on their geometry, the geometrical characteristics of the rock mass fractures (orientation and spacing) and the mechanical characteristics of the rock mass and the discontinuities. The assessment of the rock instability risk depends on the quantity and quality of the available information on the rock mass and the analysis methods used for the evaluation of the mechanical behavior of the rock block collection. Different sites of natural rock slopes, of road cuts, and of open-cast mines and quarries, described in the present document, show that the known information can vary a lot from one site to the other. The steps of data gathering and analysis, then the modelling step used to analyze the stability of the rock slope, lead to uncertainties. The present work deals in particular with the influence of the geometrical uncertainties, and the different clustering methods, to define families of fractures, are examined. The combination of works suggested by several authors leads to a new method called PSMY. This method, together with the spectral method, was coded in the Mathematica platform, and the obtained results are compared with "hand-made" clusters, done with the DIPS software. The clustering methods are presented according to the ratio of classified orientations. The orientation and spacing of fracture families are fitted by statistical law. The statistical parameters are compared according to the clustering method used. These parameters have an influence on the construction of the rock mass geometrical model, called DFN (Discrete Fracture Network). The influence of the clusters on the stability analysis is studied from the stochastic models based on the limit equilibrium analysis, in the SWEDGE and RESOBLOK software. These programs do not take into account the same uncertainties, and as a result, they give different stability indicators. A sensitivity analysis of these indicators (number of unstable blocks, average volume of unstable blocks, and total volume of unstable blocks) versus the clustering methods used, and the orientation of the slopes, is carried out. A variance analysis allows an evaluation of the influence of these factors. The assessment of the global stability condition of the rock mass, depending on the cohesion and the friction angle, is proposed. The influence of the modeling method is analyzed by comparing 3D calculations using the limit equilibrium calculations, and 2D and 3D models using discrete rigid and deformable blocks. A coupling between RESOBLOK (limit equilibrium) and LMGC90 (discrete elements) allows the comparison of results on the same original geometry. For the case of Ax-les-Thermes road-cut, and for various unstable geometries, the influence of the model parameters is tested. Several cases are compared. The 3D simulation of an excavation, at different steps, is performed, and the mobilization index is studied, in order to compare several types of contacts, within the LMGC model, in relation to the possible sliding of blocks, at those different steps

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41

Duda, Tomáš. "Statické řešení střešní konstrukce". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226743.

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The subject of the diploma thesis is the design and static analysis of roof structure. It is prestressed roof shell (membrane) supported by a cable. The whole thesis is divided into several separated units according to task's specification. The text section describes the introduction to the issue of presstressed suspension cable constructions and displays their possible shapes, types and realizations. There is also technical report of solved shell, which was written on the base of the documents, drawn drawings and structural (static) analysis.

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42

Moura, Nícolas Rodrigues. "Contribution to the study of the effect of three-dimensional stress states to slope stability analysis". Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8904.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Análises de estabilidade de taludes são predominantemente realizadas em duas-dimensões (2D) por métodos de equilíbrio limite. Os métodos convencionais de equilíbrio limite são alvos de muitas críticas pelo o uso do equilíbrio estático, pressuposições de forças na análise e por possuir o mesmo fator de segurança ao longo de toda a superfície de deslizamento. Para superar essas deficiências, o método proposto por Kulhawy (1969) incorpora o comportamento tensão-deformação do solo com tensões oriundas do Método de Elementos Finitos (FEM) e tem a mesma estrutura dos métodos de equilíbrio dos métodos de equilíbrio de equilíbrio limite clássicos. É também chamado de método aperfeiçoado. Devido à existência de taludes com geometrias complexas, a abordagem tridimensional (3D) é a única capaz de incorporar todos os aspectos geométricos do problema. Esta dissertação é dividida em dois artigos com o tema de estabilidade de taludes pelo o método de Kulhawy em abordagens 2D e 3D. O objetivo primário dessa dissertação é avaliar os principais fatores que influenciam a estabilidade de taludes. O primeiro artigo propôs geometrias variando de convexo a côncavo em um conjunto de propriedades típicas de solos. Duas trajetórias de geração de tensões in- situ foram utilizadas, i.e., construção e escavação. O método GLE foi calculado para fins de comparação. A superfície de deslizamento é muito dependente do histórico de tensão e da forma da face do talude. A diferença relativa no estado de tensões inicial típico alcançou 15% nas análises 2D e 34% nas análises 3D. A análise de sensibilidade do efeito do Poisson no fator de segurança mostrou-se muito relevante. A relação entre os fatores de segurança 2D e 3D são quase lineares independente do estado de tensões, das propriedades de resistência, formato da face do talude, na ordem de 30 a 40%. O segundo artigo propõe análises em barragens construídas em vales estreitos. Três abordagens de análises foram utilizadas: redução de resistência ao cisalhamento (SSR), métodos de Kulhawy e GLE. Condições típicas de fundações são muito variáveis como topografia e deformabilidade. A análise de sensibilidade do módulo de fundação de Young no fator de segurança foi insignificante em 2D e relevantes em 3D. A relação entre o comprimento do aterro (W) e a altura () é uma variável representativa do grau de estreitamento da barragem e na estabilidade de taludes. A análise de deformações planas tende a altas relações W/H e o oposto mostra elevados efeitos 3D. A inclinação da ombreira mostrou-se relevante no fator de segurança apenas em aterros em vales estreitos. Fundações mais rígidas são mais beneficias para o fator de segurança devido à produção de altos efeitos de arqueamento neste cenário. O método de Kulhawy provou-se ser vantajoso pela a incorporação do comportamento mecânico do solo, o uso de tensões mais realísticas nas análises e avaliação da estabilidade local na superfície de deslizamento. Isso aumenta a quantidade de informações úteis e confiáveis para o profissional de engenharia no projeto de taludes. Todas as análises foram realizadas usando o software SoilVision Systems, Saskatchewan, Canadá. Os módulos utilizados foram o SVLOPE, SVSOLID e o SVFLUX (SoilVision Systems Ltd., 2018). A análise de tensão para a simulação de trajetórias de escavação e construção utilizou do solucionador de Equações Diferenciais Parcias (PDE) o FlexPDE 6 (PDE Solutions Inc., 2014).
Slope stability analyses are predominantly performed using the two-dimensional (2D) conventional limit equilibrium methods. Conventional limit equilibrium methods are targets of many criticisms for using static equilibrium, assumptions of forces in the analysis and the same factor of safety along the slip surface. In order to overcome these shortcomings, the method proposed by Kulhawy (1969) incorporates the stress-strain behavior of the soil with stresses from the Finite Element Method (FEM) with the same structure as limit equilibrium methods. It is also called enhanced method. Due to the existence of slopes with complex geometries, the three-dimensional (3D) approach is only able to incorporate all the geometric aspects of the problem. This thesis is divided into two papers with the subject of slope stability analyses by the Kulhawy’s method in 2D and 3D approaches. The primary objective of this thesis is to evaluate major factors that influence slope stability. The first paper proposed geometries ranging from convex to concave in a set of soil properties. Two stress paths were considered, i.e., construction and excavation. The GLE method was computed for comparison purposes. The slip surface is very dependent on the stress history and the shape of slope face. The relative difference in typical initial stress state reached 15% in 2D analyses and 34% in 3D analyses. Sensitivity analysis of effect of Poisson’s ratio on factor of safety was very relevant. The relationship between 2D and 3D factors of safety are nearly linear independent of stress state on order of 30 to 40%. The second paper propose analyses on embankment dams built in narrow valleys. Three approaches of slope stability were used: shear strength reduction (SSR), Kulhawy’s and GLE methods. The typical conditions of foundation sites are very variable as topography and deformability. Sensitivity analysis of Young’s modulus of foundation on factor of safety was insignificant in 2D and relevant in 3D analyses. The ratio between embankment length (W) and height (H) was very important on slope stability. The plane strain analysis tends to high W/H ratio and the opposite shows high 3D effects. The inclination of abutment showed to be relevant on factor of safety only in embankments in narrow valleys. Stiffer foundations are beneficial to the factor of safety due producing high arching effects in this scenario. The Kulhawy’s method proved to be advantageous by the incorporation of mechanical behavior of soil, more realistic stress and local stability evaluation on slip surface. It increases the amount of useful and reliable information to the engineering professional in design of slopes. All analyses were performed using SoilVision Systems suite software, Saskatchewan, Canada. The modules used were SVSLOPE, SVSOLID and SVFLUX (SoilVision Systems Ltd., 2018). The stress analysis for the simulation of excavation and construction trajectories used partial differential equation (PDE) solver, FlexPDE 6 (PDE Solutions Inc., 2014).

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43

Mazzotti, Sofia. "Equilibri nel modello di Cournot quando esistono limiti di capacità produttiva". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13564/.

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L'obiettivo di questa tesi è quello di applicare alcune nozioni tipiche dei sistemi dinamici discreti a una situazione economica. Si considerano vari casi di oligopolio, secondo il modello di Cournot, e si osserva che un sistema di n competitori inizia a essere instabile con l'aumentare di n. Si approfondisce poi il caso di un duopolio simmetrico in cui i competitori hanno limitate capacità produttive. Se ne studiano i punti di equilibrio e la loro stabilità e, considerando la funzione di reazione, si osserva che le variazioni degli attrattori prodotte da cambiamenti dei parametri nella funzione dei costi sono dovute alle border-collision bifurcations, cioè all'urto di tali attrattori con le discontinuità della funzione di reazione. Si danno in ultimo alcuni strumenti per trovare i bacini di attrazione.

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44

Martins, João Filipe Correia. "Do Monsanto ao aeroporto. 2ª circular: entre limite e interface". Master's thesis, Faculdade de Arquitetura de Lisboa, 2012. http://hdl.handle.net/10400.5/5773.

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45

Rua, Sandra Cristina Camacho Gomes. "Essays in macroeconomics with general equilibrium models". Doctoral thesis, Instituto Superior de Economia e Gestão, 2014. http://hdl.handle.net/10400.5/7543.

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Doutoramento em Economia
Modelos de equilíbrio geral são largamente usados na academia e em instituições internacionais. Aqui, questões relacionadas com reformas estruturais, o limite inferior das taxas de juro e sua relação com opções de política são analisadas com um modelo de larga escala. Os principais resultados são: reformas estruturais unilaterais são benéficas e coordenação nacional tem vantagens; com as taxas de juro no limite inferior, políticas orçamentais e estruturais podem aliviar uma recessão e reduzir o tempo em que esse limite é activo. Mas a eficácia depende do instrumento orçamental e das características das reformas. Seguidamente, modelos estimados de media-escala são usados para avaliar a importância de choques antecipados nos EUA. Primeiro, avalia-se o papel destes choques na dinâmica do mercado habitacional e conclui-se que são importantes nas flutuações deste mercado e em particular nos ciclos de boom-bust. Expectativas de inquéritos sao usadas como validação externa do modelo. Depois, o papel de choques antecipados de politica monetária e analisado num modelo de ciclo económico. Conclui-se que melhoram a desempenho do modelo sem causar problemas de identificação; explicam uma percentagem maior das flutuações das variáveis observadas que choques não antecipados de politica monetária; e ajudam a melhor replicar covariâncias de algumas variáveis.
General equilibrium models are widely used in academia and policy institutions. Here, issues related to structural reforms, the zero lower bound and its interaction with policy options are analysed with a large-scale calibrated model of the euro area. The main find- ings are: unilateral structural reforms are beneficial and cross-country coordination has advantages; at the zero bound, fiscal and structural policies can alleviate a recession and reduce the time spent at the bound but their effectiveness depends on the fiscal instrument and the design of the reforms. Then, medium-scale estimated models are used to assess the importance of news shocks in the US. First, the role of news in housing market dynamics is investigated. Results show that news shocks are important for housing market fiuctua- tions, and in particular boom-busts cycles. Survey-based expectations are used as external validation of the model. Then, the role of monetary policy news shocks is analysed in a business cycle model. Results show they improve the performance of the model without leading to identification problems; they account for a larger fraction of the fiuctuations in observables than the unanticipated monetary policy shock; and they help to achieve a better matching of the covariances of some observables.

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46

Carrapatoso, Kléber. "Théorèmes asymptotiques pour les équations de Boltzmann et de Landau". Phd thesis, Université Paris Dauphine - Paris IX, 2013. http://tel.archives-ouvertes.fr/tel-00920455.

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Nous nous intéressons dans cette thèse à la théorie cinétique et aux systèmes de particules dans le cadre des équations de Boltzmann et Landau. Premièrement, nous étudions la dérivation des équations cinétiques comme des limites de champ moyen des systèmes de particules, en utilisant le concept de propagation du chaos. Plus précisément, nous étudions les probabilités chaotiques sur l'espace de phase de ces systèmes de particules : la sphère de Boltzmann, qui correspond à l'espace de phase d'un système de particules qui évolue conservant le moment et l'énergie ; et la sphère de Kac, correspondant à un système de particules qui conserve seulement l'énergie. Ensuite, nous nous intéressons à la propagation du chaos, avec des estimations quantitatives et uniforme en temps, pour les équations de Boltzmann et Landau. Deuxièmement, nous étudions le comportement asymptotique en temps grand des solutions de l'équation de Landau.

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47

Saraiva, Gustavo Quinderé. "Modelos de equilíbrio geral dinâmico com custo de default". reponame:Repositório Institucional do FGV, 2013. http://hdl.handle.net/10438/11059.

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This work consists on a survey of some papers from the literature of general equilibrium with default costs. We focus on the study of Kehoe and Levine (1993) and Alvarez and Jermann (2000) models. We also describe some adaptations of Al- varez and Jermann’s model, such as the models developed by Hellwig and Lorenzoni (2009) and Azariadis and Kaas (2008), and we compare them with Huggett’s (1993) model, where the market is exogenously incomplete. Finally, we point out one flaw present in Krueger and Perry’s (2010) algorithm to compute stationary equilibria from economies such as Alvarez and Jermann.
Neste trabalho fazemos um resumo de alguns artigos que tratam de equilíbrio geral dinâmico com custos de default. Focamos no estudo dos modelos de Kehoe e Levine (1993) e de Alvarez e Jermann (2000). Também descrevemos algumas adaptações do modelo de Alvarez e Jermann, como os trabalhos de Hellwig e Lorenzoni (2009) e de Azariadis e Kaas (2008), e comparamos os resultados desses modelos com os de Huggett (1993), no qual os mercados são exogenamente incompletos. Finalmente, expomos uma falha no algoritmo computacional sugerido por Krueger e Perry (2010) para se computar os equilíbrios estacionários de economias como as de Alvarez e Jermann (2000).

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48

Sharma, Sushank. "Transition laminaire turbulent dans les couches limites supersoniques : différents scénarios et contrôle possible Control of oblique-type breakdown in a supersonic boundary layer employing streaks Turbulent flow topology in supersonic boundary layer with wall heat transfer Laminar-to-turbulent transition in supersonic boundary layer : : Effects of initial perturbation and wall heat transfer Effect of thermo-mechanical non-equilibrium on the onset of transition in supersonic boundary layers". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR16.

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Les simulations numériques directes (DNS) des couches limites supersoniques adiabatiques et isothermes (chauffées et refroidies) sont effectuées. Deux différents scénarios de transition, à savoir la décomposition de type oblique et la transition de type 'by-pass', sont présentés en détail. Pour le scénario de transition de type oblique, les résultats montrent que les modes contrôles avec un nombre d'onde quatre à cinq fois supérieur au nombre fondamental se révèlent être bénéfiques pour contrôler la transition. Dans la première région après le forçage du mode de contrôle, la distorsion de flux moyenne (MFD) bénéfique générée en induisant le mode de contrôle est uniquement responsable de l'entrave à la croissance du mode fondamental. Globalement, le MFD et la partie tridimensionnelle du contrôle contribuent également à contrôler la rupture oblique. Les effets de paramètres physiques tels que la température de paroi, l'intensité de la perturbation et le 'baseflow' sont étudiés pour la transition de 'By-pass'. Les résultats concernant le scénario de by-pass révèlent que l'augmentation de l'intensité de la perturbation déplace le début de la transition en amont et augmente également la longueur de la région de transition. De plus, en dessous de 1 % des niveaux de perturbation, le refroidissement de la paroi stabilise le flux, tandis que l'inverse se produit à des valeurs plus élevées. L'existence d'un non-équilibre thermomécanique avance le début de la transition pour les cas chauffés alors que la paroi refroidie se comporte dans le sens opposé. Les analyses de la couche limite turbulente montrent que les facteurs thermiques influencent la topologie et l'inclinaison des structures tourbillonnaires. De plus, en ce qui concerne le flux de chaleur, un processus de transfert différent est dominant dans la région proche paroi pour la paroi refroidie
Direct numerical simulations (DNS) of both adiabatic and isothermal (heated and cooled) supersonic boundary layers are performed. Two different transition scenarios, namely the Oblique-type breakdown and the By-pass transition are presented in detail. For the oblique-type transition scenario, the results show that the control modes with four to five times the fundamental wavenumber are beneficial for controlling the transition. In the first region, after the control-mode forcing, the beneficial mean-flow distortion (MFD) generated by inducing the control mode is solely responsible for hampering the growth of the fundamental-mode. Globally, the MFD and the three-dimensional part of the control contribute equally towards controlling the oblique breakdown. Effects of physical parameters like wall-temperature, perturbation intensity and baseflow are investigated for the By-pass transition. The results regarding the by-pass scenario reveal that increasing the perturbation intensity moves the transition onset upstream and also increases the length of the transition region. Additionally, below 1% perturbation levels, wall-cooling stabilizes the flow while inverse happens at higher values. The existence of the thermo-mechanical non-equilibrium advances the onset of transition for the heated cases while the cooled wall behaves in the opposite sense. The analyses of the turbulent boundary layer show that the thermal factors influence the topology and inclination of the vortical structures. Moreover, regarding the heat flux, different transfer process is dominant in the near-wall region for the cooled wall

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Ismaïli, Anisse. "Algorithms for Nash-equilibria in Agent Networks and for Pareto-efficiency in State Space Search : Generalizations to Pareto-Nash in Multiple Objective Games". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066148.

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Un agent est un élément qui décide une action. Par ce formalisme très général on peut aussi bien désigner deux enfants jouant à pierre-papier-ciseaux, des êtres humains choisissant des produits sur un marché, un logiciel de routage calculant un plus court chemin sur Internet pour transporter des informations sur des routes numériques encombrées, qu’une enchère combinatoire automatique pour vendre des liens commerciaux et rapportant des milliards à google. Les chercheurs en théorie de la décision algorithmique et en théorie des jeux algorithmique – des mathématiciens et informaticiens – aiment à penser que ces exemples concrets peuvent être modélisés au moyen de systèmes décisionnels rationnels, aussi complexe la réalité soit-elle. Les systèmes décisionnels modernes trouvent leur complexité dans plusieurs dimensions. D’une part, les préférences d’un agent peuvent être complexes à représenter avec de simples nombres réels, alors que de multiples objectifs conflictuels interviennent dans chaque décision. D’une autre part, les interactions entre agents font que les récompenses de chacun dépendent des actions de tous, rendant difficile la prédiction des actions individualistes résultantes. L’objet de cette thèse en théorie algorithmique des systèmes décisionnels interactifs (jeux) est de poursuivre des efforts de recherche menés sur ces deux sources de complexité, et in fine, de considérer les deux complexités dans un même modèle
An agent is an entity that decides an action. By using this abstraction, it is possible to model two children playing rock-paper-scissors, a software computing a shortest path on the internet for packet-routing on congest numerical networks, as well as an automatic combinatorial auction that sells commercial links in order to make google earn billions. The researchers in algorithmic decision theory and algorithmic game theory (mathematicians and computer scientists) like to think that these real-life examples can be modelled by mean of agents in an interaction decision system, no matter how complex is reality. The modern interactive decision systems find their complexity in multiple aspects. Firstly, the preferences of an agent can be complex to model with real numbers when there are multiple conflicting objectives resulting from every decision. Secondly, the interactions between agents are such that the payoff of every individual depends of the actions of all, making difficult the prediction of the resulting action-profile. This thesis aims at pursuing research efforts lead on these two sources of complexity, in order to consider ultimately both aspects in the same model

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50

Sitta, Martin. "Montovaná železobetonová konstrukce výrobní haly s administrativou". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265275.

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As the main topic this thesis describes the design and evaluation of selected reinforced concrete members of the prefabricated reinforced concrete industrial building with administration at ultimate limit state in accordance with applicable standards. Movable overhead crane with carrying capacity of 50 tons is the main distinction of the industrial hall. Lateral frame whit main structural parts which are roof prestressed girder, load-bearing column supporting the overhead crane and drilled pile transferring loads from the upper construction to the load bearing subsoil, is designed in particular. Furthermore, design of the Gerber beam which forms the slab construction in the administrational part of the building is elaborated. Structural design and evaluation of other structures of the building is not part of this thesis.

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Tesis sobre el tema "Limit equilibrium"

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