Made available in DSpace on 2015-05-08T14:53:42Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1223967 bytes, checksum: e7ddc07e077e29ba4df142948034d2a8 (MD5) Previous issue date: 2010-06-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The constant technological evolution and the globalization phenomena have been aroused organizations to looking for both new ways to deal with the market and the new environmental business. Among these new ways of dealing with the market it is the Business Social Responsibility that is beginning to making part of the policy and companies principles. On this perspective, this study attempts to analyze in a general way how a company in the food sector, located in Ceará state, behaves itself with respect to the Business Social Responsibility principles through the stakeholders perception set who are directly and indirectly involved and have information about the company under analysis. The research was based on three-dimensional Carroll`s model (1979), which seeks to fully understand the essentials aspects of corporative social performance according to the dimensions of the categories of social responsibility (economic, legal, ethical and voluntary), the types of response behavior (reactive, defensive, accommodative and proactive), and the actions areas/company programs (consumption, environment, discrimination, product safety and security in the work). The work is classified as a case study of descriptive-exploratory character that through a qualitative and quantitative approach carried out through fields research, where were applied interviews with a semi-structured guide, evaluated through analysis of the information content, and questionnaires to the internal and external stakeholders that not take part in the company. The data were evaluated by using the STATATM program. The results showed that the internal stakeholders perceive that the company has operations predominantly in the economic responsibility field, especially in the administration and production employees view, indicating that the actions are focused on profit maximization. But, for the managers, stands up the legal responsibility, as well as for the external stakeholders like customers, community and suppliers. Now the consumers and partners emphasized that the company assumes financial and voluntary responsibility respectively, indicating that the company develops social actions that enhance the community quality life in its surroundings. In the behavior and response fields it can be observed in the point of view of three of the five external stakeholders types the predominance of proactive behavior (community, suppliers and partners), but for customers and consumers the company has accommodative behavior. For the internal stakeholders predominated the feeling that the activities are having developed as a means to obey the requirements, being, therefore, defensive. In relation to the actions/programs, it is perceived that was unanimous between all internal and external stakeholders, that for this company the product security is the basis of its performance in the food market. In a general way, the application of the methodology proposed by Carroll (1979) allowed to concluded that in the stakeholders perception the company do not have structured policies of RSE acting in a punctual manner through an Educational Institute, which develops activities specifically for capacity building. / A constante evolução tecnológica e a globalização têm despertado as organizações para uma procura intensa por novas formas de lidar com o mercado e com a nova conjuntura empresarial. Dentre essas novas formas de lidar com o mercado está a Responsabilidade Social Empresarial que está começando a fazer parte da política e dos princípios das empresas. Sobre essa perspectiva, esta pesquisa objetiva analisar como uma empresa do setor alimentício, localizada no estado do Ceará, se comporta quanto aos princípios da Responsabilidade Social Empresarial por meio da percepção do conjunto de stakeholders que direta e indiretamente estejam envolvidos e que possuam informações sobre a empresa em análise. A pesquisa baseou-se no modelo tridimensional de Carroll (1979), que busca compreender de forma integral os aspectos essenciais da performance social corporativa de acordo com as dimensões de categorias de Responsabilidade Social (econômica, legal, ética e voluntária); os tipos de comportamento de resposta (reativa, defensiva, acomodativa e pró-ativa); e as áreas de ações/programas da empresa (consumo, meio ambiente, discriminação, segurança do produto e segurança no trabalho). O trabalho classifica-se como estudo de caso de caráter descritivo-exploratório que por meio de uma abordagem quali-quantitativa realizada através de pesquisas de campo, aplicou-se entrevista com roteiro semi-estruturado, avaliadas através de análise de conteúdo das informações, e questionários a stakeholders internos e externos à empresa, analisados por meio do programa STATATM. Os resultados apontaram que os stakeholders internos vêem que a empresa possui atuação predominantemente no campo de responsabilidade econômica, principalmente na visão dos funcionários da administração e produção, evidenciando que as ações se voltam para a maximização de lucros. Mas para os gestores sobressai-se a responsabilidade legal, assim como também os stakeholders externos do tipo clientes, comunidade e fornecedores. Já os consumidores e parceiros salientam que a empresa assume responsabilidade econômica e voluntária respectivamente, denotando que a empresa desenvolve ações sociais que elevam a qualidade de vida da comunidade que fica ao seu entorno. No campo de comportamentos e respostas pode-se observar na visão de três dos cinco tipos de stakeholders externos a predominância de comportamento pró-ativo (comunidade, fornecedores e parceiros), mas para clientes e consumidores a empresa possui comportamento acomodativo. Para os stakeholders internos predominou que as atividades se desenvolvem como meio de obedecer às exigências, sendo, portanto, defensivo. Em relação às ações/programas, percebe-se que foi unânime entre todos os stakeholders internos e externos, que para essa empresa, a segurança do produto é a base de sua atuação no mercado de alimentos. De modo geral, a aplicação da metodologia de Carroll (1979) permitiu concluir que na percepção dos stakeholders a empresa não possui políticas estruturadas de RSE, atuando de forma pontual por meio de um Instituto Educacional, o qual desenvolve atividades especificamente de formação profissional.

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2015-10-22T19:24:12Z No. of bitstreams: 2 Dissertação - Roger Otávio Pires Montes - 2015.pdf: 8169771 bytes, checksum: e580ffb280dfa5136f41ab38cf0aec4e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-23T11:04:48Z (GMT) No. of bitstreams: 2 Dissertação - Roger Otávio Pires Montes - 2015.pdf: 8169771 bytes, checksum: e580ffb280dfa5136f41ab38cf0aec4e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-23T11:04:48Z (GMT). No. of bitstreams: 2 Dissertação - Roger Otávio Pires Montes - 2015.pdf: 8169771 bytes, checksum: e580ffb280dfa5136f41ab38cf0aec4e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-05-25 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / This master’s thesis analyses the free and forced nonlinear vibrations of a simply supported functionally graded cylindrical shell which the material’s properties are described by gradient’s law along the shell’s thickness. The nonlinear equations of motion are obtained using nonlinear theories Donnell and Sanders, where the field displacements and field strain of nonlinear Donnell’s shallow shell theory is obtained as a simplification of the nonlinear Sanders’s formulation. The effects of the internal fluid, that is incompressible, irrotational and inviscid and it has been described as a potential velocity to consider the fluid-structure interaction, and the influence of a thermal field in the nonlinear dynamic behavior of the functionally graded cylindrical shell will be investigated. It is developed a low-dimensional model, wherein the shell of the system equilibrium equations is solved by an analytical procedure, which yields the longitudinal and circumferential displacement field as a function of transverse displacement, satisfying the boundary conditions problem. The determination of transverse displacement is obtained by the perturbation techiniques, which enables the achievement of the main nonlinear modes that should be present in the displacement fields of the functionally grade cylindrical shell. To analyze the nonlinear free vibration, it is applied the Galerkin-Urabe method to obtain the system of non-linear algebraic equations, and then resolved by the Newton-Raphson method. The results show the influence of functional gradation, geometry, the effect of the internal fluid, considering a fluid-filled shell, and the thermal action of the nonlinear free vibrations of the shell by the frequency-amplitude relations. Finally, a parametric analysis to study the nonlinear forced vibrations of the cylindrical shell subjected to a harmonic loading side for some geometric relations is conducted. In this case the system of ordinary differential equations of second order in time is obtained from the application of the Galerkin method and integrated over time from the Runge-Kutta fourth order method. The results evaluates the influence of the internal fluid and the thermal effects in the nonlinear oscillation of functionally graded cylindrical shell, using the resonances’ curves, the basins’ attraction, time responses and the phase portraits. / Nesta dissertação são analisadas as vibrações, livres e forçadas, não lineares de uma casca cilíndrica simplesmente apoiada feita com um material com gradação funcional, que as propriedades dos materiais constituintes são descritas por determinadas leis de gradação ao longo da espessura. As equações não lineares de movimento são obtidas utilizando-se as teorias não lineares de Donnell e de Sanders, sendo que os campos de deslocamentos e as deformações referentes à teoria não linear de Donnell para cascas abatidas podem ser obtidos como uma simplificação da formulação não linear de Sanders. Serão investigados os efeitos da presença de um fluido interno, incompressível, não viscoso e irrotacional, sendo descrito a partir de um potencial de velocidade, considerando a interação fluido-estrutura, além da influência de um campo térmico no comportamento dinâmico não linear da casca cilíndrica com gradação funcional. É desenvolvido um modelo de baixa dimensão, em que o sistema de equações de equilíbrio da casca é resolvido através de um procedimento analítico, o qual permite obter os campos de deslocamento axial e circunferencial em função dos deslocamentos transversais, além de atender as condições de contorno do problema. A determinação dos deslocamentos transversais é feita a partir do método da perturbação, o qual possibilita a obtenção dos principais modos não lineares que devem estar presentes nos campos de deslocamentos da casca cilíndrica. Para analisar as vibrações livres não lineares, aplica-se o método de Galerkin-Urabe para se obter o sistema de equações algébricas não lineares, sendo, em seguida, resolvido a partir do método de Newton-Raphson. Os resultados mostram a influência da gradação funcional, da geometria, do efeito do fluido interno, considerando uma casca totalmente preenchida, e da ação térmica nas vibrações livres não lineares da casca por meio das relações frequência-amplitude. Por fim, é feita uma análise paramétrica das vibrações forçadas não lineares da casca cilíndrica submetida a um carregamento lateral harmônico para algumas relações geométricas. Neste caso o sistema de equações diferenciais ordinárias de segunda ordem no tempo é obtido a partir da aplicação do método de Galerkin e integrado ao longo do tempo a partir do método de Runge-Kutta de quarta ordem. Da mesma forma avalia-se a influência do fluido interno e dos efeitos térmicos nas oscilações não lineares da casca cilíndrica com gradação funcional, utilizando-se as curvas de ressonância, as bacias de atração, as respostas no tempo e os planos fase.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-03-29T15:39:07Z No. of bitstreams: 2 Dissertação - Henrique Araujo Rodrigues Sattler - 2015.pdf: 3327262 bytes, checksum: 1c260793f2aa5b49f25d29e6835ab326 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-03-29T15:41:36Z (GMT) No. of bitstreams: 2 Dissertação - Henrique Araujo Rodrigues Sattler - 2015.pdf: 3327262 bytes, checksum: 1c260793f2aa5b49f25d29e6835ab326 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-03-29T15:41:37Z (GMT). No. of bitstreams: 2 Dissertação - Henrique Araujo Rodrigues Sattler - 2015.pdf: 3327262 bytes, checksum: 1c260793f2aa5b49f25d29e6835ab326 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work is a study of linear and nonlinear free vibration of a cylindrical panel simply supported subjected to a dependent loading time. From the full potential and kinetic energy functional of a cylindrical panel to determine the system's equations of motion, whereas the field of deformations of the cylindrical panel follows the non-linear theory for Donnell shallow shell. For discretization of the cylindrical panel moving system of equations is performed a test procedure able to obtain the fields axial and circumferential displacements from a modal expansion radial displacement field, creating a low-dimensional discretized model. Determine the radial displacement field from perturbation techniques that provides the nonlinear modes which couple to the linear vibration mode of the system from the quadratic and cubic non-linearities present in the cylindrical panel equilibrium equations. With this system of equations is reduced to a partial differential equation as a function of the expansion of the modal amplitudes for the radial displacement being discretized then the Galerkin method. They present the results of various free, linear and non-linear vibrations, and forced into a cylindrical simply supported panel, showing the remarkable influence of the modal coupling in modal solution to this radial displacement and the panel geometry. / Neste trabalho, realiza-se um estudo das vibrações livres, lineares e não lineares, e forçadas de um painel cilíndrico simplesmente apoiado submetido a um carregamento dependente do tempo. A partir dos funcionais de energia potencial total e cinética de um painel cilíndrico, determinam-se as equações de movimento do sistema, considerando que o campo de deformações do painel cilíndrico segue a teoria não linear de Donnell para cascas abatidas. Para obter a discretização do sistema de equações de movimento do painel cilíndrico, realiza-se um procedimento analítico capaz de obter os campos de deslocamentos axial e circunferencial a partir de uma expansão modal para campo de deslocamento radial, criando um modelo discretizado de baixa dimensão. Determina-se o campo de deslocamentos radiais a partir de técnicas de perturbação que fornece os modos não lineares que se acoplam ao modo linear de vibração do sistema a partir das não linearidades quadráticas e cúbicas presentes nas equações de equilíbrio do painel cilíndrico. Com isto o sistema de equações é reduzido para uma equação diferencial parcial em função das amplitudes modais da expansão para o deslocamento radial, sendo discretizada, em seguida, pelo método de Galerkin. Apresentam-se diversos resultados das vibrações livres, lineares e não-lineares, e forçadas para um painel cilíndrico simplesmente apoiado, mostrando a marcante influência do acoplamento modal presente na solução modal para os deslocamentos radiais e da geometria do painel.

The aim of this thesis is to scan the part of the interior and exterior of the Faculty of Electrical Engineering and Communication building using the FARO Focus3D X 130 scanner, and the creation of a 3D model in the WGS 84 system. Subsequently, methods, status and utilization research of this technology and point cloud processing software is provided. The collected data are processed in the SCENE. Three-dimensional model is designed using the Pointfuse and Microstation V8i programs. In the end, the registration accuracy of the scans and the resulting 3D model accuracy are evaluated.

The main aim of this diploma thesis is to propose for changes in the company information system. Document content is focuse on analyse, implementation and using data warehouse and usage advance to optimaze methods for achievement added value to users. The first part of this thesis is focused on choice of suitable concept of data warehouse, implementation and possible problems. In the second part, I compare assets of this system with costs for development and administration.

Dans cette thèse, nous construisons un modèle de liaisons fortes tridimensionnel minimal pour les cuprates supraconducteurs monocouches à base de lanthane. Celui-ci prend en compte huit orbitales, dont deux d'entre elles impliquent les ions oxygène apicaux. L'optimisation des paramètres microscopiques permet de reproduire presque parfaitement la bande de conduction tridimensionnelle telle qu'elle a été obtenue à partir des calculs DFT. Nous discutons la façon dont chacun des paramètres entrant en jeu dans ce modèle multi-bandes influence la bande de conduction, et nous montrons que la forme particulière de sa dispersion contraint les valeurs des paramètres. Nous mettons alors en évidence que la détermination standard d'un modèle effectif à une bande au travers d'un traitement perturbatif converge lentement en raison de la valeur relativement faible du gap de transfert de charges. A ce stade, cela nous permet, en revanche, de lever le voile sur l'origine microscopique des amplitudes de saut des électrons au sein des plans et en-dehors des plans. Une approche alternative au calcul des paramètres microscopiques de saut du modèle effectif de liaisons fortes est présentée et mise à contribution. Il en résulte que l'accord avec la DFT est préservé à condition que les amplitudes de saut de plus longue portée soient conservées. Une comparaison avec les modèles existants est également effectuée. La surface de Fermi, mettant en exergue des domaines décalés qui alternent en taille et en forme, est comparée à l'expérience. De plus, la densité d'états du modèle est aussi calculée. Une analyse plus approfondie du modèle est réalisée au travers d'une étude en couplage faible des instabilités magnétiques. Les calculs sont effectués sur de grandes cellules et nous avons trouvé une compétition parmi plusieurs instabilités magnétiques tridimensionnelles dans la région d’intérêt du dopage en trous accessible expérimentalement. Bien qu'à notre connaissance cela ne semble pas avoir été évoqué expérimentalement, nous montrons à l'issue de notre étude, que la tendance du modèle à former des ondes de densité de spin incommensurables tridimensionnelles est la plus forte à proximité du dopage 1/8. / In this thesis, we construct a minimal three-dimensional tight-binding model for single-layer La-based cuprate superconductors. It entails eight orbitals, two of them involving apical oxygen ions. Parameter optimization allows to almost perfectly reproduce the three-dimensional conduction band as obtained from DFT. We discuss how each parameter entering this multiband model influences it, and show that the peculiar form of its dispersion severely constraints the parameter values. We then evidence that standard perturbative derivation of an effective one-band model is poorly converging because of the comparatively small value of the charge transfer gap. Yet, this allows us to unravel the microscopical origin of the in-plane and out-of-plane hopping amplitudes. An alternative approach to the computation of the tight-binding parameters of the effective model is presented and worked out. It results that the agreement with DFT is preserved provided longer-ranged hopping amplitudes are retained. A comparison with existing models is performed, too. The Fermi surface, showing staggered pieces alternating in size and shape, is compared to experiment. The density of states is calculated as well. The model is further analyzed through a weak coupling study of magnetic instabilities. It is performed on large clusters and competition between several three-dimensional magnetic instabilities in the hole-doping region of experimental interest is found. We show that the tendency to form a three-dimensional incommensurate spin density wave is strongest in the vicinity of 1/8 doping.

Les intoxications médicamenteuses volontaires répétées (IMVr) constituent un problème de santé publique croissant, mais sous-évalué et traité comme une conduite suicidaire, alors qu’elles appartiendraient au registre des addictions. Notre travail abonde dans ce sens en montrant que les suicides alcoolisés se font principalement par IMV et correspondent au deliberate self-harm syndrom ; les suicidants récidivants se distinguent par un névrosisme et un attachement anxieux typiques des addictions ; les IMVr même suicidaires témoignent d’une relation addictive aux médicaments ; le facteur le plus prédictif d’IMV serait de l’avoir envisagée. Conceptualisé de façon translationnelle et argumenté par une approche pharmacologique, nous proposons un modèle dimensionnel des conduites suicidaires, intégré au continuum des addictions, confirmant l’hypothèse initiale et l’intérêt d’un raisonnement transnosographique diagnostique et thérapeutique dans le champ des pathologies mentales. / Repeated Self-poisoning (RSP) constitute an under evaluated but growing public health problem, treated as a suicidal rather than an addictive behavior. Our work brings arguments by showing that suicides involving alcohol are mainly by self-poisoning and correspond to deliberate self-harm syndrome; repeat suicide attempters are identified by a neuroticism and anxious attachment typically found in addicts; even suicidal RSP shows addictive behavior involving medicines; the best predictor of self-poisoning is having thought about it. Conceptualized through a translational approach and supported by pharmacological arguments, we propose a multidimensional model of suicidal behaviors, that could integrate the continuum of addictive behaviors. This confirms the initial hypothesis and the viability of a transnosographic concept for diagnosis and treatment of mental illnesses.

Denna studie syftar till att analysera diskursen kring flyktingar i media. Mer specifikt jämförs diskursen i artiklar kring flyktingar från Syrien respektive flyktingar från Ukraina. Artiklarna bryts ner i avsikt att finna återkommande mönster. Två teman kan utläsas som återkommande: dels porträttering av flyktingar som utsatta, dels porträttering av flyktingar som en belastning. I studien används ramverket kritisk diskursanalys som är såväl en modell som en teori - där relationen mellan språkbruk och maktutövning i samhället analyseras. Inom den kritiska diskursanalysen används analysverktyget Faircloughs tredimensionella modell som beskriver språkbruk i tre dimensioner: text, diskursiv praktik och social praktik. I denna studie ligger huvudfokuset på att analysera texten, men den diskursiva och sociala praktiken analyseras och diskuteras också. Resultatet av studien indikerar att flyktingar från Ukraina och Syrien porträtteras något olika i tidningarna Aftonbladet och Dagens Nyheter. Syriska flyktingar porträtteras i högre utsträckning som en belastning än ukrainska flyktingar / This study aims to analyse the discourse on refugees in the media. More specifically, it compares the discourse in articles on refugees from Syria and refugees from Ukraine. The articles are broken down to find recurring patterns. Two themes can be identified as recurring: portrayal of refugees as vulnerable and portrayal of refugees as a burden. The study uses the framework of critical discourse analysis, which is a model as well as a theory that analyses the relationship between language use and the exercise of power in society. Within critical discourse analysis, the analytical tool Fairclough's three-dimensional model is used, which describes language use in three dimensions: text, discursive practice, and social practice. In this study, the focus is on analysing the text, but the discursive and social practices are also analysed and discussed. The results of the study indicate that refugees from Ukraine and Syria are portrayed somewhat differently in the newspapers. Syrian refugees are portrayed as a burden to a greater extent than Ukrainian refugees.

Master of Engineering (Research) / Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.

Master of Engineering (Research) / Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.