• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 87
  • 38
  • 22
  • 22
  • 20
  • 8
  • 6
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 251
  • 52
  • 34
  • 30
  • 27
  • 26
  • 26
  • 21
  • 20
  • 19
  • 19
  • 17
  • 16
  • 16
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Schaktfri ledningsbyggnad : En kostnadsanalys mellan styrd borrning och konventionell schaktning / Trenchless pipeline installation : A cost analysis between directional drilling and traditional excavation

Andersson, Sophia, Jonsén, Oscar January 2019 (has links)
Styrd borrning är en schaktfri metod för att förlägga ledningar i mark. Examensarbetet har utförts i samarbete med Styrud Ingenjörsfirma AB som uppfattat en okunskap i branschen över prisbilden för styrd borrning. Syftet med arbetet är att utföra en kostnadsanalys för att beskriva hur styrd borrning står sig ekonomiskt mot konventionell schaktning. Arbetet undersöker även vilka faktorer som påverkar en eventuell ekonomisk brytpunkt, vilken i detta arbete definieras som den punkt när en viss metod blir det ekonomiskt gynnsamma alternativet. Studien har utformats för att så objektivt som möjligt belysa ämnet med utgångspunkten att göra metoderna jämförbara analytiskt. För att genomföra en analys har en beräkningsmodell skapats. Målet med modellen och dess utformning är att den enkelt skall gå att bygga vidare på och utvecklas i framtiden samt att användas av projektörer som en fingervisning tidigt i projekteringsstadiet. Från beräkningsmodellen har 70 fiktiva fall studerats. Resultatet visar att styrd borrning är billigare i 73% av fallen. I övriga fall tyder resultatet på att styrd borrning som metod generellt sett inte är så dyrt att övervägning att använda metoden försvinner. Genom resultat och analys dras slutsatsen att styrd borrning i de flesta fall står sig ekonomiskt starkt som alternativ till konventionell schaktning. / Horizontal directional drilling is a trenchless method used to install pipelines underground. This thesis is conducted in collaboration with Styrud Ingenjörsfirma AB, who perceived lacking knowledge within the industry regarding the financial aspects of directional drilling. The purpose of this thesis is to carry out a cost analysis that defines how directional drilling stands financially against traditional excavation. The study also intends to describe which factors that influence a possible economic breakpoint, in this study referring to when a certain method becomes the economically strongest alternative. This thesis has been carried out to as objectively as possible describe the topic focusing on making the methods analytically comparable. To carry out the analysis, an economic model has been created. The model and its design have been created in a manner that makes it easy to develop it in the future and aims to act as a guide for project planners to indicate which method to proceed with. From the economic model, 70 cases have been studied. The result shows that directional drilling is cheaper in 73% of the cases. In the rest of the cases, the result suggests that directional drilling as a method generally is not so expensive that consideration of using the method disappears. Through results and analysis, it is concluded that directional drilling in most cases is a strong alternative to traditional excavation from an economic standpoint.
172

PLANTING DEPTH OF TREES - A SURVEY OF FIELD DEPTH, EFFECT OF DEEP PLANTING, AND REMEDIATION

Rathjens, Richard G. 03 September 2009 (has links)
No description available.
173

[pt] AVALIAÇÃO DO COMPORTAMENTO DE ESCAVAÇÃO GRAMPEADA INSTRUMENTADA EM SOLO DE PEDREGULHO / [en] EVALUATION OF THE BEHAVIOR OF AN INSTRUMENTED SOIL NAILED EXCAVATION IN GRAVEL SOIL

FERNANDO CHAVEZ CARMEN 01 February 2022 (has links)
[pt] Nos últimos anos na cidade de Lima as escavações profundas alcançaram uma presença maior, devido à recente demanda pela construção de edifícios altos e centros comerciais com vários níveis de subsolos, onde utilizam-se preferencialmente as cortinas atirantadas para a contenção dos solos. No entanto, a técnica de solo grampeado mostra-se como uma alternativa interessante, dado que também permite fornecer suporte lateral e limitar os movimentos do solo. A técnica consiste em reforçar o bloco do solo atrás da parede através das inclusões passivas, criando uma estrutura de gravidade consistente que permite aumentar a resistência geral ao cisalhamento e restringir os deslocamentos. Este estudo de caso procura avaliar os deslocamentos horizontais em uma escavação de 15m de altura em um entorno urbano, onde o solo é predominantemente de pedregulho denso mal graduado, parte do depósito aluvial do Conglomerado de Lima. A estimativa dos parâmetros de resistência baseou-se em ensaios de cisalhamento direto in situ em grande escala e ensaios de arrancamento encontrados na literatura. O acompanhamento dos deslocamentos ao longo do processo construtivo, foi realizado a través de inclinômetros instalados no perímetro, em locais estratégicos para avaliar os deslocamentos mais críticos na escavação. A avaliação de erros sistemáticos em inclinômetros é também abordada no estudo. Complementarmente, realizaram-se análises numéricas com programas de equilíbrio limite e elementos finitos, que permitiram avaliar os fatores de segurança e os deslocamentos com o objetivo de comparar os dados de campo com os resultados calculados. Através de análise paramétrica e calibração do modelo foi possível conhecer a influência dos parâmetros geotécnicos e geométricos de escavações profundas grampeadas. / [en] In recent years in the city of Lima, the execution of deep excavations growth, due to the recent demand for the construction of high-rise buildings and shopping malls having various levels of basements, where anchorage walls systems are preferably used to soil retention. However, the soil nailing technique is an interesting alternative, by reason to provide lateral support and limit movements. The soil nailing technique consists of reinforcing the soil block behind the wall through passive inclusions, producing a consistent gravity structure that allows the increas of the shear strength and restricting displacements. This case study aims to evaluate the horizontal displacements generated in a 15m high deep excavation in an urban environment, where the existing soil is predominantly of poorly graded dense gravel, component of the alluvial deposit of the Lima Conglomerate. The estimate of strength parameters for this type of soil was based on large-scale in situ direct shear tests and pullout tests found in the literature. The monitoring of displacements throughout the construction process was carried out using vertical inclinometers installed on the perimeter, in strategic locations to assess the most critical displacements that the excavation could experience. The evaluation of systematic errors in inclinometers is also approached in the study. In addition, numerical analyzes were carried out with limit equilibrium and finite element programs, which allowed evaluating the safety factors and displacements in order to compare the field data with the calculated results. Through parametric analysis and model calibration, it was possible to know the influence of geotechnical and geometric parameters of nailed deep excavations.
174

Kalaureia 1894 : A Cultural History of the First Swedish Excavation in Greece

Berg, Ingrid January 2016 (has links)
The excavation of the Sanctuary of Poseidon at Kalaureia in 1894 marks the beginning of Swedish archaeological fieldwork in Greece. During a couple of hot summer months, two philologists from Uppsala University, Sam Wide (1861-1918) and Lennart Kjellberg (1857-1936), worked in the sanctuary together with the architect Sven Kristenson (1858-1937), the Greek foreman Pankalos and around twenty local workmen. In 1997, the Swedish Institute at Athens began new excavations at the sanctuary. This thesis examines the beginnings of Swedish fieldwork in Greece. Within the framework of a cultural history of archaeology, inspired by archaeological ethnography and the New Cultural History, it explores how archaeology functioned as a cultural practice in the late nineteenth century. A micro-historical methodology makes use of a wide array of different source material connected to the excavation of 1894, its prelude and aftermath. The thesis takes the theoretical position that the premises for archaeological knowledge production are outcomes of contemporary power structures and cultural politics. Through an analysis of how the archaeologists constructed their self-images through a set of idealized stereotypes of bourgeois masculinity, academic politics of belonging is highlighted. The politics of belonging existed also on a national level, where the Swedish archaeologists entered into a competition with other foreign actors to claim heritage sites in Greece. The idealization of classical Greece as a birthplace of Western values, in combination with contemporary colonial and racist cultural frameworks in Europe, created particular gazes through which the modern country was appropriated and judged. These factors all shaped the practices through which archaeological knowledge was created at Kalaureia. Some excavations tend to have extensive afterlives through the production of histories of archaeology. Therefore, this thesis also explores the representations of the 1894 excavation in the historiography of Swedish classical archaeology. It highlights the strategies by which the excavation at Kalaureia has served to legitimize further Swedish engagements in Greek archaeology, and explores the way in which historiography shapes our professional identities.
175

Ermeneutica e semiotica in archeologia : per una nuova interpretazione culturale della ceramica vascolare nell’Egitto greco-romano. / Herméneutique et sémiotique dans l’archéologie : pour une nouvelle interprétation culturelle de la céramique des vases dans l’Égypte gréco-romain / Hermeneutics and Semiotics in Archaeology : a new cultural interpretation of ceramics in Greco-Roman Egypt

Caputo, Clementina 30 July 2014 (has links)
Cette recherche de doctorat concerne l’étude des fragments céramiques utilisés comme supports pour l’écriture dans l'Égypte gréco-romaine, c'est-à-dire les ostraca. Les deux groupes d'ostraca, objet de cette analyse, proviennent des fouilles archéologiques modernes effectuées dans deux sites qui se trouvent dans le désert occidental égyptien : Dime es-Seba/Soknopaiou Nesos (Fayoum) et Amheida/Trimithis (Dakhla). Le deux sites sont respectivement fouillés par la Mission archéologique du Centro di Studi Papirologici dell'Universita del Salento-Lecce (2003-2012) et de l’Université de New York -ISAW (2004-2013). Les aspects liés à la matérialité des ostraca (des fragments de récipients en céramique utilisés généralement pour écrire des textes en grec et démotique) ont été complètement ignorés par le passé en faveur de l’étude du texte. La raison principale de cette négligence est liée à la qualité médiocre du matériel céramique, considéré sans valeur. Par ailleurs, les études de céramologie en Égypte ainsi que l’étude des circuits économiques dans lesquels la poterie était utilisée sont très récents. En outre, il est communément admis que les scribes ramassait les fragments de céramique au hasard dans des dépotoirs et que n’y avait pas de sélection dans le choix des supports. Notre recherche démontre que ce concept est une fausse supposition, au moins pour ce qui concerne les deux groupes d'ostraca examinés. En revanche, il est clair que les scribes faisaient un choix sélectif des tessons selon leurs besoins et que, dans certains cas, il y avait une fragmentation ultérieure des morceaux. Rien a été laissé au hasard: le contenu des textes était strictement adapté à la nature de tessons utilisés comme support. De plus, la classification de la céramique des deux sites a été un point essentiel pour mettre en rapport la culture matérielle et l’organisation de la société égyptienne qui l’a produite entre le IIIe siècle av. J.-C. et le IVe siècle apr. J.-C. / This doctoral dissertation focuses on the study of the pottery sherds that were used as writing surfaces for painted texts in Greco-Roman Egypt, called ostraka. Two groups of ostraka found in two modern excavations, Dime es-Seba/Soknopaiou Nesos (Fayyum), and Amheida/Trimithis (Dakhla Oasis) are the main subjects of the investigation. The two archaeological sites are under excavation by, respectively, the Centro di Studi Papirologici dell’Università del Salento-Lecce (2003-2012), and New York University-ISAW (2004-2013).Both settlements are located in the Western Desert of Egypt, in areas far from the Nile Valley and the main centers of power. The ostraka, which are re-used broken fragments of ceramic vessels with texts in Greek and Demotic, have been in the past seldom considered as archaeological objects because of the predominant importance of their texts. The material part of the ostraka being made from pottery vessels generally unrefined and of poor quality, have deterred most scholars from studying them accurately. Moreover, ceramological studies in Egypt and the interest towards the economy of the pottery manufacture and re-use are very recent. Finally, it is commonly believed that scribes collected the ceramic fragments to be used as ostraka randomly from open-air dumps. This research proved that this concept has to be considered as a wrong assumption, at least for the two groups of ostraka examined. On the contrary, it is very clear that the ancient scribes made a proper selection of the sherds they needed for specific purposes and that in some cases they reworked the sherds. It seems clear that nothing was left to the chance: the content of the texts and their use is strictly related to the kind of potsherds used to hold it. Additionally, the study of the ceramic types used in both settlements, analyzed as signifiers of the cultural environments for which they were produced, has shed light to the complex society of Egypt between the third century BCE and the fourth century CE.
176

Análise numérica tridimensional de túneis considerando não linearidade do suporte de concreto projetado reforçado com aço / Three-dimensional numerical analysis of tunnels considering nonlinear properties of steel reinforced shotcrete support

Jamal, Fernando Galvanin 27 September 2013 (has links)
Pesquisas e projetos envolvendo a complexa interação de maciços rochosos com estruturas de suporte de túneis evoluem constantemente. A adoção de modelos numéricos sofisticados aliada ao desenvolvimento de computadores com capacidade de processamento crescente possibilitam representações mecânicas de processos complexos. Para análises geotécnicas, considerações de resistência, deformabilidade e condutividade hidráulica do maciço são encontradas em códigos computacionais com representações próximas das encontradas nas pesquisas experimentais de vanguarda da área. Por outro lado, estes mesmos códigos atribuem com frequência ao comportamento do concreto reforçado representações simplistas, muitas vezes com base na teoria da elasticidade. Implicações econômicas e de incerteza na avaliação da segurança decorrem desta forma de representação. Esta pesquisa visa a contribuir para análises da interação entre maciço e suporte de uma escavação subterrânea. Para tanto foram elaboradas simulações numéricas considerando técnicas consagradas de avaliação mecânica de uma escavação, aliadas a uma representação do concreto reforçado considerando o marcante efeito de fissuração. Com foco no comportamento do concreto foram desenvolvidas simulações numéricas de distintas estruturas de concreto reforçado selecionadas na literatura e que contam com boa instrumentação e caracterização mecânica adequada de seus materiais. Os resultados obtidos indicam a possibilidade da avaliação concomitante das complexas características do maciço assim como do concreto reforçado. Este fato contribui para a avaliação da segurança de uma escavação subterrânea com possíveis repercussões no custo das obras. / Research and projects involving the intricate interaction between rock mass and tunnel support structures constantly evolve. The adoption of sophisticated numerical models allied to the development of computers with an increasing processing capacity allows mechanical representations of complex processes. For geotechnical analysis, considerations on rock mass strength, deformability and hydraulic conductivity are found in computational codes with representations close to those found in vanguard experimental research of this subject. However, these same codes often attribute simplistic representations to reinforced concrete behavior, frequently based on elasticity theory. Economic and uncertainty implications in safety evaluation result from this sort of representation. This research aims to contribute to analysis of interaction between rock mass and support of an underground excavation. Thus, numerical simulations were elaborated considering established techniques of mechanical evaluation of excavations, allied to a reinforced concrete representation taking into account the prominent effect of cracking. Focused on the concrete behavior, there were developed numerical simulations of distinct reinforced concrete structures selected in literature and that rely on fair instrumentation and adequate mechanical characterization of the involved materials. The results indicate the possibility of concomitant evaluation of the rock mass complex character and the reinforced concrete. This fact contributes to safety evaluation of an underground excavation with potential repercussions on project cost.
177

Método da escavação como recurso de ensino e clínico em terapia ocupacional na perspectiva ergológica

Furtado, Eliana Maria Anjos 27 May 2010 (has links)
Submitted by CARLA MARIA GOULART DE MORAES (carlagm) on 2015-04-01T18:01:01Z No. of bitstreams: 1 ElianaFurtadoEducacao.pdf: 2297241 bytes, checksum: 41f5355a6b2adeba78d24c00a77591dd (MD5) / Made available in DSpace on 2015-04-01T18:01:01Z (GMT). No. of bitstreams: 1 ElianaFurtadoEducacao.pdf: 2297241 bytes, checksum: 41f5355a6b2adeba78d24c00a77591dd (MD5) Previous issue date: 2010-05-27 / Nenhuma / Esta tese teve como finalidade escrever sobre o campo de conhecimento da Terapia Ocupacional, pretendendo aproximar este campo ao campo da ergologia. O estudo está fundamentado teoricamente pelos pressupostos da educação, educação e trabalho, ergologia, saberes, experiência, fenomenologia da percepção e hermenêutica fenomenológica. O campo de estudo principal é a Terapia Ocupacional. O objetivo geral deste estudo foi investigar se a proposta do método da escavação, como método de ensino e clínico em Terapia Ocupacional, poderá se constituir em um Dispositivo Dinâmico a Três Pólos da Abordagem Ergológica, a partir da experimentação e da confrontação, entre os saberes produzidos neste processo e os saberes da formação, dos alunos participantes do Grupo de Estudos sobre Atividade Humana. Neste estudo, utilizamos a pesquisa qualitativa, por ser esta a mais adequada devido à especificidade deste estudo, uma vez que o mesmo exigiu uma multiplicidade de materiais originários de diversas fontes. Este estudo foi de cunho qualitativo do tipo exploratório, estudo de caso. A pesquisa também envolveu levantamento documental, entrevistas e registros de observações sistemática do grupo de estudos sobre atividades humanas. A análise da pesquisa foi realizada por meio da triangulação de fontes e da hermenêutica dialética. Por meio da análise do estudo de caso, foi possível inferir que, neste processo, vivido na experiência do grupo, houve a confrontação entre os saberes da formação, a empiria dos alunos e os saberes aprendidos na experiência do grupo e também o entrecruzamento destes saberes, possibilitando aos discentes a renormatização da formação e a ressignificação da vida cotidiana e de trabalho. A proposta do método da escavação foi o dispositivo que possibilitou a circularidade dos saberes formais e da empiria nos vários espaços em que a formação se insere, oportunizando aos discentes reavaliarem o seu conhecimento, produzirem um novo olhar sobre as tecnologias da Terapia Ocupacional e vivenciarem uma nova forma de analisar as atividades a partir da auto-escavação. A proposta do método também proporcionou o ressignificar e renormatizar as atividades de trabalho dos discentes, assim como o território profissional, garantindo e reafirmando com isso o poder terapêutico da atividade, respeitando sua historicidade, temporalidade e contexto social. A proposta do processo de escavação, utilizado como dispositivo de análise das experiências e percepções vividas no grupo, constituiu-se em um Dispositivo Dinâmico a Três Pólos da Abordagem Ergológica, uma vez que os alunos que participaram deste grupo, ao analisarem as atividades realizadas, as tecnologias da Terapia Ocupacional, as práticas de ensino e a sua própria atividade de trabalho, confrontaram estes saberes, ressignificando-os e renormatizando-os. / This thesis was aimed to write about the field of knowledge of Occupational Therapy, intending to approach this field to the field of ergology. The study is theoretically motivated by the assumptions of education, education and work, ergology, knowledge, experience, phenomenology of perception and phenomenological hermeneutics. The main field of study is occupational therapy. The general aim of this study was to investigate whether the proposal?s method of excavation, as a method of teaching and clinical occupational therapy, may be constituted in a Dynamic dispositive to three-pole of approach ergological from the trial and confrontation, between the knowledge produced in this process and knowledge of training, of students participating in the Study Group on Human Activity. This study used the qualitative research, because this is the more appropriate given the specific nature of this study, since it required a variety of materials originating from different sources. This study is qualitative and exploratory, case study. The research also involved survey, interviews and records of systematic observations of the study group on human activities. The research analysis was performed using the triangulation of sources and dialectical hermeneutics. By analyzing the case study was possible to infer that this process, lived in the experience of the group, there was a confrontation between the knowledge of training, the empiricism of the students and the knowledge learned in the experience of the group and also the intersection of this knowledge, enabling to learners to standardize again of training and reinterpretation of everyday life and work. The proposal?s method of excavation was the device that enabled the circularity of the formal knowledge, the empirical? in the various areas where the training takes place, creating the opportunity for students to reassess their knowledge, to produce a new look at the technologies of occupational therapy and experience a new way to analyze the activities from the self-excavation. The proposal?s method also provided reframe and create a new meaning to work activities of students, as well as professional territory, thus ensuring and reaffirming the power of therapeutic activity while respecting their history, temporality, and social context. The purpose of the excavation process, used as a device for analyzing the experiences and perceptions experienced in the group, formed in a Dynamic Device to Three-Pole of the approach ergological, since students who participated in this group, while examining the activities performed, the technologies of Occupational Therapy, teaching practices and their own work activity, they confronted this knowledge, giving new meaning to them and reframing them.
178

Les fouilles françaises de Médamoud : synthèse historique et archéologique d’un temple thébain / The French excavations in Medamud : historical and archaeological study

Relats Montserrat, Félix 21 November 2016 (has links)
Les fouilles françaises de Médamoud se sont déroulées entre 1924 et 1939 sous la direction de F. Bisson de la Roque (entre 1924 et 1932) et de Cl. Robichon (entre 1933 et 1939). Elles ont mis au jour de nombreux monuments s’échelonnant de la XIe dynastie jusqu’à l’époque byzantine, mais aucune synthèse n’avait encore offert une étude globale de l’histoire du site. L’ensemble de cette documentation constitue un corpus riche mais hétérogène dont il a fallu restituer le contexte de découverte. En effet, les deux étapes des fouilles sont inégalement publiées et l’étude des archives nous a permis de reconstituer le déroulement, les modalités et les résultats des actions sur le terrain. Après avoir restitué l’histoire des fouilles et proposé une nouvelle datation des vestiges mis au jour, nous avons analysé l’état du temple depuis sa fondation. L’existence du temple primitif a ainsi été prouvée, même si nous avons modifié son plan et très largement nuancé les théories d’A. Varille quant à son usage cultuel. Ensuite, Sésostris III a refondé le temple, qui a ensuite été modifié par Thoutmosis III. Une nouvelle étude des maçonneries a permis de réfuter la présentation traditionnelle qui supposait des destructions successives du bâtiment et nous avons proposé, au contraire, qu’une partie du temple du Moyen Empire et du Nouvel Empire furent inclus par les Ptolémées dans leur propre programme architectural. Le dieu de Médamoud, Montou, a également été étudié à travers la documentation du site qui le présente comme le dieu thébain par excellence. L’essentiel du programme iconographique n’était pas consacré à l’exaltation guerrière de la divinité mais plutôt à la légitimation royale et au culte des ancêtres, parmi lesquels Sésostris III occupait une place de choix. / Medamud’s French excavations took place between 1924 and 1939 under the supervision of F. Bisson de la Roque (between 1924 and 1932) and of CL. Robichon (between 1933 and 1939). They excavated numerous monuments which spread from the XIe dynasty to the Byzantine period although there is no global overview of the history of the site. It was necessary to re-establish the discovery’s context of all of this information as the corpus of documents was extensive but heterogeneous. As the two excavation stages were unequally published, studying the archives allowed us to establish how the field actions took place, its methods and results. After having summarized the excavations’ history and offered the uncovered vestiges a new dating, we analysed the temple’s condition since its founding. In this way, the existence of the « temple primitif » has been proven even though we modified its plan and widely qualified A. Varille’s theories regarding its cult uses. Senwosret III rebuilt the temple, which was modified by Thutmose III afterwards. Thanks to a new study of the masonry, we re-examined the traditional assumption, which supposed successive destruction of the building. Instead, we believe that parts of the Middle Kingdom’s temple and of the New Kingdom’s were included by the Ptolemies in their own architectural plans. Regarding Montu the god of Medamud, he is presented as the ultimate Theban god through the site’s documentation. Most of the iconography wasn’t dedicated to the war glorification of the deity but rather to royal legitimisation and ancestor worship among which Senwosret III occupies a prominent place.
179

Estudo do comportamento geomecânico de rochas efusivas da formação serra geral e sua aplicação na modelagem numérica de túneis / The geomechanical behaviour of efusive rocks from Serra Geral Formation and its application to tunnel numerical analisys

Silveira, Felipe Gobbi January 2011 (has links)
A ocupação do espaço subterrâneo tem assumido importância crescente na sociedade atual; destaca-se no Sul do Brasil o uso de escavações subterrâneas em empreendimentos hidrelétricos, executadas nas rochas efusivas da Formação Serra Geral (FSG). Algumas destas obras registraram tensões elevadas nos maciços rochosos, as quais ocasionaram grandes prejuízos por não terem sido previstas em projetos e não terem solução adequada quando são utilizadas correlações empíricas. Tendo em vista estas dificuldades no desenvolvimento dos projetos, esta tese teve o objetivo de estudar o comportamento das rochas efusivas da FSG e utilizar os dados na simulação numérica de túneis. Foi feito o acompanhamento da execução de cerca de 650m do túnel de adução da UHE Castro Alves, tendo sido coletados os dados de geologia, resultados da instrumentação da obra e coletadas amostras das rochas encontradas no túnel. Foram realizados ensaios de laboratório em corpos de prova para determinar o comportamento tensão versus deformação destes materiais e suas envoltórias de ruptura. Foram obtidas correlações entre alguns dos parâmetros. Os parâmetros determinados nos ensaios (rocha intacta) foram extrapolados para o maciço rochoso. Diversos dados da obra, bem como o cruzamento entre eles e os parâmetros geomecânicos obtidos foram colocados em uma plataforma SIG, a qual se mostrou uma ferramenta bastante útil e de grande potencialidade para uso nestes projetos. Com os parâmetros geomecânicos determinados para o maciço foi realizada uma análise numérica 3D do túnel escavado, a partir da qual foi feita uma retro-análise dos deslocamentos medidos em campo, sendo possível estimar o valor de K0 de campo de cerca de 1,3. Foram também realizadas análises paramétricas para estudar a importância da correta estratigrafia dos derrames basálticos (especialmente a presença das brechas) e a simulação de tensões horizontais elevadas, tendo se demonstrado a necessidade de análises deste tipo para verificação de soluções adequadas em túneis em maciços com estas condicionantes. / In the present society the underground occupation has become increasingly relevant. In Southern Brazil it is possible to observe the use of underground excavation applied to tunneling for hydro electric power plants, as carried out in the Serra Geral Formation (FSG) effusive rocks. Some of these tunnels showed high stresses in the rock mass, which resulted in time and money wasted as it was not expected in the project development and also because there was not a suitable solution found when empirical correlations were applied. Considering these difficulties during the project development, this thesis studies the FSG effusive rocks behavior and the utilization of tunnel data for numerical simulations. About 650m of tunnel excavation has been monitored at the UHE Castro Alves. Geology data, instrumentation results and rock samples have been obtained. To determine the shear stress versus strain behavior, laboratory tests were carried out. The correlation between some parameters was obtained and test parameters of the intact rock were extrapolated to the rock mass. A SIG platform has been used with the field data and the geomechanical parameters; it appears to be a useful tool with great potential for this kind of work. Since the geomechanical parameters have been determined, a FEM 3D analysis was carried out; field displacements back-analysis from the 3D analysis made possible the estimation of a K0 value approximately equal to 1,3. Parametrical analyses were also carried out to study the relevance of considering the correct rock strata and the effects of high horizontal stresses on the numerical simulation results, which showed the need for this kind of analysis in tunnels excavated under these conditions.
180

Modélisation numérique du creusement d'un tunnel à l'aide d'un bouclier à pression de boue

Atahan, Cem 30 January 1995 (has links) (PDF)
Cette étude porte sur la modélisation numérique du creusement de tunnels à l'aide de boucliers à front pressurisé et notamment sur l'adaptation de la méthode du ramollissement, initialement mise au point pour le calcul, en coupe bidimensionnelle, de tunnels creusés à l'aide de procédés non mécanisés. La thèse est composée de 8 chapitres et comprend une étude bibliographique concernant le calcul des ouvrages souterrains, une analyse de la réponse du terrain à une pressurisation du front de taille à partir des calculs axisymétriques, la mise au point d'une méthode permettant de reproduire, dans un calcul plan, en coupe transversale, les effets mis en évidence en conditions axisymétriques et l'application de cette méthode à l'analyse d'un ouvrage instrumenté dans le département du Val-de-Marne. Cet ouvrage a été équipé d'inclinomètres et d'extensomètres installés dans le terrain, ainsi que de témoins à cordes vibrantes disposés dans un anneau de revêtement. Les mesures ont permis d'analyser la réponse du massif encaissant et de l'ouvrage de soutènement au cours des différentes étapes de creusement. Le creusement de cet ouvrage a été simulé à l'aide de la méthode de calcul développée dans le cadre de ce travail et les résultats de calculs confrontés à ceux donnés par les mesures.

Page generated in 0.0904 seconds