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  • 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.
81

Dynamic Response And Permanent Displacement Analysis Of Akkopru Dam

Ulgen, Deniz 01 January 2004 (has links) (PDF)
In this study, dynamic response of Akk&ouml / pr&uuml / Dam under earthquake motions is analyzed and the permanent displacements are evaluated. Initially, the critical slip surface of the dam and the corresponding yield acceleration are determined by using the computer program SLOPE. Then, by employing the finite element program SAP2000, static analyses are performed to obtain the mean effective stresses which are used in the determination of dynamic material properties of the dam. Four different scenario earthquakes having a magnitude of 7 are used in the dynamic analyses. Two of those scenarios are taken from European Strong Motion Database and the others are generated by XS artificial earthquake generation program prepared by Erdik (1992). Dynamic analyses of the dam are carried out by the finite element program TELDYN. Permanent displacements of the critical slip surface are calculated by utilizing the Newmark method. Consequently, for an earthquake having a magnitude of M=7 and a peak ground acceleration of 0.20g, the maximum permanent displacement of the dam is found to be 15.90 cm. Furthermore, the permanent displacements of the dam are calculated under base motions having different peak ground acceleration values and it is observed that the rate of increase in the amount of permanent displacements is greater than the increase in the amount of peak ground accelerations.
82

Uma metodologia para o tratamento de problemas da mecânica dos sólidos com redefinição de domínio utilizando a técnica de relaxação dinâmica

Silva, Rodrigo Mero Sarmento da 09 December 2005 (has links)
Diverse construction work of engineering involves the execution of excavation and embankments, such as the construction of foundations, dams and urban infrastructure. In general, geomechanical problems have a high degree of complexity due to the difficulty on the parameters quantification, the definition of representative models of the soil and the interaction soil-structure. Many models are based on the final arrangement of the system, not considering the intermediate analyses that are important steps in the study of those problems. In this study was developed a methodology for modeling problems that need redefinitions of analysis domain in function of the consideration of excavations and embankments, using an alternative technique for solution of the balance equations, the Dynamic Relaxation, combined with the Finite Element Methods for the development of the model. / Fundação de Amparo a Pesquisa do Estado de Alagoas / Diversas obras de engenharia envolvem a execução de escavações e aterros, a exemplo da construção de fundações, barragens e infra-estrutura urbana. De um modo geral, a modelagem desses tipos de problemas possui um grau de complexidade alto devido à dificuldade da quantificação de parâmetros, de definição dos modelos representativos do solo e da interação solo-estrutura. Muitas modelagens baseiam-se no arranjo final do sistema, dispensando as análises intermediárias que correspondem a passos importantes no estudo desses problemas. Neste trabalho desenvolve-se uma metodologia para modelagem de problemas que necessitam de redefinições de domínios de análise em função da consideração de escavações e aterros, utilizando-se uma técnica alternativa para solução das equações de equilíbrio, a Relaxação Dinâmica, em conjunto com o Método dos Elementos Finitos para discretização do modelo.
83

Resistivity and Seismic Characterization of an Embankment Dam. A Case Study in Northern Sweden / Resistivitet och seismisk karaktärisering av en jordfyllningsdamm. Ett fältarbete i norra Sverige

Polín-Tornero, Álvaro January 2018 (has links)
The main cause of failure in embankment dams - which represent 75% of all dams in the world (ICOLD, 2018) - is the internal erosion produced by excessive seepage not accounted for in their designs. This erosion can cause that a small anomalous structure, not likely to be considered as risky, turns rapidly into a significant structural damage if not recognized on time. This creates a necessity for methods that can detect these anomalies in a non-intrusive, cost-effective and sensitive way. The purpose of this work is to analyse the strength of three geophysical methods (ERT and Seismic Refraction and Reflection) in detecting and accurately localizing anomalous structures inside an embankment dam. This study has been successfully approached in two different ways: by synthetic modelling and by an experimental field work at an embankment dam in northern Sweden. The results show that these methods are capable of detecting different structures in the interior of the dam in an accurate and rapid manner. / Den främsta orsaken till brister i jordfyllningsdammar, som utgör 75% av alla dammar i världen (ICOLD, 2018) och är föremål för detta arbete, är inre erosion som orsakas av extrem läckage som togs inte med i beräkningar i deras konstruktioner. Denna erosion kan resultera i att en liten anomal struktur, som sannolikt inte anses vara riskabel, snabbt blir en betydande strukturell skada om den inte är uppmärksammas i tid. Därför krävs metoder som kan upptäcka dessa anomalier på ett icke-påträngande, kostnadseffektivt och känsligt sätt. Syftet med detta arbete är att analysera möjligheterna med tre geofysiska metoder (ERT, Seismisk Refraktion och Seismisk Reflektion) för att upptäcka och exakt lokalisera anomala strukturer inuti en jordfyllningsdamm. Denna studie har utförts på två fronter: genom (i) syntetisk modellering och (ii) ett experimentellt fältarbete vid en damm i norra Sverige. Resultaten visar att dessa metoder kan detektera olika strukturer inuti dammen på ett pålitligt och snabbt sätt.
84

Comportamento dos aterros que compõem a obra do Arco Metropolitano do Rio de Janeiro. / Behaviour of embankments that compose the arco metropolitano from Rio de Janeiro.

Caroline Sidrim Gomes Leite Mansur Antunes 06 June 2012 (has links)
O presente trabalho tem como objetivo a análise do comportamento dos aterros instrumentados que compõem a obra do Arco Metropolitano do Rio de Janeiro. Os resultados da instrumentação de campo serão discutidos e retroanalisados, juntamente com dados disponíveis na literatura, buscando-se a definição de parâmetros confiáveis, representativos do comportamento da argila compressível da região em estudo. O Arco Metropolitano do Rio de Janeiro é uma rodovia projetada que servirá como ligação entre as 5 principais rodovias que cortam o município do Rio de Janeiro. Dada a magnitude da obra e a ocorrência de significativas espessuras de solos moles em alguns trechos da região, determinados aterros que compõem a rodovia foram instrumentados com placas de recalque e inclinômetros, instalados em diferentes estações de monitoramento, no intuito de avaliar os deslocamentos verticais e horizontais dos aterros durante o processo construtivo. De posse de parâmetros confiáveis, procede-se à simulação numérica do processo construtivo de um dos aterros, a partir do programa PLAXIS, de elementos finitos. Os resultados numéricos são confrontados com a instrumentação de campo (fornecida por placas de recalque) e com os resultados de previsões teóricas (teoria de adensamento unidimensional). Em projetos de aterros sobre solos compressíveis, a instrumentação geotécnica é de grande importância, pois permite acompanhar o desenvolvimento de todo o processo construtivo, e as deformações decorrentes da sobrecarga imposta pelo lançamento de camadas de aterro. A imposição de um carregamento sobre solos de alta compressibilidade e baixa resistência pode acarretar em grandes deformações ao longo do tempo, além de rupturas indesejáveis do solo de fundação. Os resultados comprovaram que a modelagem numérica mostrou-se uma ferramenta adequada para a previsão dos recalques totais e tempos de adensamento. A definição de parâmetros representativos, com base em ensaios executados em amostras de boa qualidade, é o primeiro passo para a previsão coerente da evolução dos recalques com o tempo. A retroanálise do comportamento de aterros sobre solos moles permite a reavaliação das premissas de projeto, uma vez que as limitações das teorias de análise e a dificuldade na seleção de parâmetros, muitas vezes acarretam em estimativas de recalque incoerentes com as observações de campo. / The present work aims to analyze instrumented embankments behavior that composes the Rio de Janeiros Arco Metropolitano construction. Field instruments results will be discussed and reanalyzed, altogether with data available in literature, seeking to define reliable parameters, representative of the compressible clay behavior into the studied area. The Rio de Janeiros Arco Metropolitano is a road designed to work as a link between the five major highways that cross Rio de Janeiro city. Given to the works magnitude and the occurrence of significant thickness of soft soil in some parts of the region, some landfills that form the highway were instrumented with inclinometers and settlement plates installed in different monitoring stations in order to evaluate the vertical and horizontal landfill during the construction process. Armed with reliable parameters, it will be carried out to the numerical simulation of the construction process of a landfill, from the program PLAXIS, of finite elements. The numerical results will be compared with field instrumentation (provided by boards of repression) and the results of theoretical predictions (one-dimensional consolidation theory). In projects of embankments on compressible soil, geotechnical instrumentation is very important because it allows following the development of the entire construction process and the deformations due to overload imposed by the release of embankment layers. The imposition of a load on soils high compressibility and low resistance can lead to large deformations over time and undesirable disruptions in foundation soil. Concerning the numerical modeling, results proved to be a suitable tool to total settlements and times of consolidation prediction. The representative parameters definition, based on tests performed on good quality samples, is the first step for predicting the development of coherent repression with time. The reanalysis of the embankments behavior on soft soil permits the revaluation of the premises of the project, since the theory limitations of analysis and the difficulty in selecting parameters often leads to inconsistent estimates of repression with field observations.
85

Détection et évaluation des fuites à travers les ouvrages hydrauliques en remblai, par analyse des températures réparties, mesurées par fibre optique / Use of temperature measurements as a monitoring tool for earthen hydraulic structures, leakage detection and estimation of their intensity.

Cunat, Pierre 08 March 2012 (has links)
Les fuites au travers des ouvrages hydrauliques en remblai sont les signes précurseurs d'un dysfonctionnementdu dispositif d'étanchéité de l'ouvrage pouvant entraîner leur rupture. La détectionprécoce des fuites et leur quanti_cation est donc primordiale.Les méthodes géophysiques et thermométriques à grand rendement apportent des éléments deréponse pour la détection des fuites, le long des ouvrages à long linéaire, mais l'estimation de leurvitesse, nécessaire à l'évaluation de la dangerosité des fuites, n'est pas encore satisfaisante.Cette étude porte sur la détection et quanti_cation des fuites à travers les ouvrages hydrauliquesen remblai soumis à une charge d'eau permanente. Les méthodes proposées exploitent des mesures detempératures naturelles du sol à l'aide de _bres optiques placées sous le talus amont ou aval.Deux modèles de quanti_cation ont été développés et testés sur les données d'un site expérimentalcontrôlé et d'un site réel. Les résultats obtenus concordent avec les mesures de vitesse e_ectuées surles deux sites. / Leakages through embankment dams are early warning signs of a sealing malfunction and couldlead to its breakdown. Early detection of leakages and their quanti_cation is essential.High output geophysical and thermometric methods provide some answers for leakage detectionalong long linear embankment dams, but their velocity estimations necessary to assess the danger ofleakages, is not yet satisfactory.This study focuses on the detection and the quanti_cation of leakages through embankment damsunder hydraulic head. The proposed method use natural temperature measurements from the groundusing optical _ber buried under the upstream or downstream face.Two models of quanti_cation were developed and tested on data from an experimental site and a realsite. Results are consistent with velocity measurements made at both side.
86

Comportamento dos aterros que compõem a obra do Arco Metropolitano do Rio de Janeiro. / Behaviour of embankments that compose the arco metropolitano from Rio de Janeiro.

Caroline Sidrim Gomes Leite Mansur Antunes 06 June 2012 (has links)
O presente trabalho tem como objetivo a análise do comportamento dos aterros instrumentados que compõem a obra do Arco Metropolitano do Rio de Janeiro. Os resultados da instrumentação de campo serão discutidos e retroanalisados, juntamente com dados disponíveis na literatura, buscando-se a definição de parâmetros confiáveis, representativos do comportamento da argila compressível da região em estudo. O Arco Metropolitano do Rio de Janeiro é uma rodovia projetada que servirá como ligação entre as 5 principais rodovias que cortam o município do Rio de Janeiro. Dada a magnitude da obra e a ocorrência de significativas espessuras de solos moles em alguns trechos da região, determinados aterros que compõem a rodovia foram instrumentados com placas de recalque e inclinômetros, instalados em diferentes estações de monitoramento, no intuito de avaliar os deslocamentos verticais e horizontais dos aterros durante o processo construtivo. De posse de parâmetros confiáveis, procede-se à simulação numérica do processo construtivo de um dos aterros, a partir do programa PLAXIS, de elementos finitos. Os resultados numéricos são confrontados com a instrumentação de campo (fornecida por placas de recalque) e com os resultados de previsões teóricas (teoria de adensamento unidimensional). Em projetos de aterros sobre solos compressíveis, a instrumentação geotécnica é de grande importância, pois permite acompanhar o desenvolvimento de todo o processo construtivo, e as deformações decorrentes da sobrecarga imposta pelo lançamento de camadas de aterro. A imposição de um carregamento sobre solos de alta compressibilidade e baixa resistência pode acarretar em grandes deformações ao longo do tempo, além de rupturas indesejáveis do solo de fundação. Os resultados comprovaram que a modelagem numérica mostrou-se uma ferramenta adequada para a previsão dos recalques totais e tempos de adensamento. A definição de parâmetros representativos, com base em ensaios executados em amostras de boa qualidade, é o primeiro passo para a previsão coerente da evolução dos recalques com o tempo. A retroanálise do comportamento de aterros sobre solos moles permite a reavaliação das premissas de projeto, uma vez que as limitações das teorias de análise e a dificuldade na seleção de parâmetros, muitas vezes acarretam em estimativas de recalque incoerentes com as observações de campo. / The present work aims to analyze instrumented embankments behavior that composes the Rio de Janeiros Arco Metropolitano construction. Field instruments results will be discussed and reanalyzed, altogether with data available in literature, seeking to define reliable parameters, representative of the compressible clay behavior into the studied area. The Rio de Janeiros Arco Metropolitano is a road designed to work as a link between the five major highways that cross Rio de Janeiro city. Given to the works magnitude and the occurrence of significant thickness of soft soil in some parts of the region, some landfills that form the highway were instrumented with inclinometers and settlement plates installed in different monitoring stations in order to evaluate the vertical and horizontal landfill during the construction process. Armed with reliable parameters, it will be carried out to the numerical simulation of the construction process of a landfill, from the program PLAXIS, of finite elements. The numerical results will be compared with field instrumentation (provided by boards of repression) and the results of theoretical predictions (one-dimensional consolidation theory). In projects of embankments on compressible soil, geotechnical instrumentation is very important because it allows following the development of the entire construction process and the deformations due to overload imposed by the release of embankment layers. The imposition of a load on soils high compressibility and low resistance can lead to large deformations over time and undesirable disruptions in foundation soil. Concerning the numerical modeling, results proved to be a suitable tool to total settlements and times of consolidation prediction. The representative parameters definition, based on tests performed on good quality samples, is the first step for predicting the development of coherent repression with time. The reanalysis of the embankments behavior on soft soil permits the revaluation of the premises of the project, since the theory limitations of analysis and the difficulty in selecting parameters often leads to inconsistent estimates of repression with field observations.
87

Tubulações enterradas: \"o uso da trincheira induzida\" / Buried pipes: \"the use of induced trench\"

Orlando Kannebley Melotti 09 August 2002 (has links)
Atualmente a otimização e redução de custos verificados na fabricação de tubulações está caminhando para um limite. Toda e qualquer modificação no processo produtivo exige grandes investimentos com retorno a prazos cada vez maiores. Assim, a possibilidade de poder contar com técnicas que permitam a redução de esforços sobre tubulações enterradas traz sem dúvida uma importante contribuição. Este trabalho estuda o uso da trincheira como forma de reduzir os esforços que atuam sobre condutos enterrados, utilizando duas séries de ensaios denominados \"A\" e \"B\". Cada série é composta basicamente de quatro combinações diferentes, com variações geométricas da relação de altura relativa (h/B) e largura relativa (b/B). A série B teve a posição relativa (H/B) da camada flexível modificada em relação à série A. Os ensaios realizados no Departamento de Geotecnia da Escola de Engenharia de São Carlos apresentam como resultado uma redução dos esforços da ordem de 44% a 86% em relação ao ensaio de referência montado sem o uso da camada indutora. / Nowadays the optimization and the reduction of costs verified in the pipes production are walking for a limit. All and whatever modification on the productive process demands great investments with larger time return. Thus, the possibility of taking account with techniques that allows reduction efforts on buried pipes bring without any doubt, an important contribution. This work studies the induced trench to reduce the efforts that act over buried conduits, using two series, \"A\" and \"B\", with four treatments each one. The A series is composed with four different combinations. These combinations have geometric variation between relative height (h/B) and relative width (b/B) of flexible layers, were built directly over the trap door. The \"B\" series is composed with the same geometric flexible layer used in series \"A\", and they have their relative position (H/B) modified. The treatments were conducted at the \"Departamento de Geotecnia\" da \"Escola de Engenharia de São Carlos\". The results obtained were a reduction of the 44 to 86% on the efforts in relation to the reference treatment built without the use of an induced layer.
88

Experimental Study of Breach Mechanics in Overtopped Noncohesive Earthen Embankments

Al-Riffai, Mahmoud January 2014 (has links)
A comprehensive experimental program dealing with three-dimensional overtopping and breach development as well as two-dimensional overtopping physical tests of noncohesive earth embankments has been conducted on scale models in the Hydraulic Laboratory at the Department of Civil Engineering at the University of Ottawa. The experimental program which consisted of three phases focused on geotechnical and hydraulic aspects of the embankment breach mechanism. The first two phases focused on two test series for the three-dimensional breach overtopping tests: drainage and compaction. The test series were designed to determine the embankment breach characteristics using test parameters which have not been adequately identified or controlled in past noncohesive physical models: initial soil-water state and optimum dry unit weight. Both parameters were controlled in laboratory tests by means of compaction effort and seepage through the embankment body, respectively. The dynamic compaction technique employed in the preliminary experimental phase was refined to represent a more realistic method. A novel method was thus designed to simulate the construction of a real-size prototype embankment, where a vibratory and static load was used to apply and control, respectively, the compaction effort. The hydraulic aspects of the embankment breach mechanism were also investigated. For the first time, scale series tests have been used to assess the Froude criterion using tilted and quasi-exact geometric scales under very low inflow within the scope of three-dimensional breach overtopping. Data measurements included a time-history of water surface levels and video footage captured from three locations: upstream, downstream and above the embankment models. The analysis for the spatial breach overtopping tests involved measurement of the breach outflow hydrograph and breach channel evolution at the upstream slope, using hydrologic routing and a developed photogrammetric technique using the video footage, respectively. An expression which estimates the breach outflow based on this apparent upstream control section was therefore derived. The relationship between the measured and estimated breach outflow was expressed in terms of breach discharge efficiency. The third phase of the experimental program was comprised of two-dimensional overtopping tests to investigate the erodibility of a steep slope in overtopped noncohesive embankment models. A novel experimental two-dimensional configuration used to measure the pore-water-pressures within the embankment model body was developed using micro and standard tensiometer-transducer-probe assemblies, designed, assembled and tested at the Geotechnical Engineering Laboratory. A transient flownet analysis was developed using ArcGIS and the time-history of the pore-water-pressure measurements. All flow parameters were computed using the free water surface and bed profiles captured using a photogrammetric technique and the developed hydrologic routing method. Using the one-dimensional Saint-Venant equations, an analytical expression for the bed shear stress was derived to take into account the effects of unsteady flow, boundary seepage and steep slopes. Using the measured erosion rates and the sediment continuity principle, the bed mobility relationship expressed by the Shields and transport parameters was revisited to account for the effects of unsteady and supercritical flow on a downstream steep slope in the presence of boundary seepage. This novel transient flownet approach will lead to the development of new sediment mobility relationships for breach flows, instead of the classical sediment transport-capacity formulations which are based on steady, subcritical and normal flow conditions.
89

Urbanisticko architektonické řešení nábřeží řeky Svitavy v Brně / Urban architectural design of the selected area by the river Svitava in Brno

Rohrerová, Aneta January 2015 (has links)
The main objective of the proposal, processed in the thesis is editing the waterfront in the selected area Husovice and change the purpose of the current premises of the former Mosilana. The Island defined from the east River Svitava and from the west Mlýnský náhon offer housing funktion, possibilities of recreation in the public space with city character, as well as the public space with natural character. The former area Mosilana serve as a new commercial center with several smaller squares, shops, restaurants, café, information center, newspaper, studios, workshops, exhibition spaces, galleries and views of significant element - Svitava. Emphasis is put on the biking and walking trails on the right embankment of the river Svitavy. Also important is the arrangement of street Valchařská.
90

Predicting surfacing internal erosion in moraine core dams

Rönnqvist, Hans January 2010 (has links)
Dams that comprise broadly and widely graded glacial materials, such as moraines, have been found to be susceptible to internal erosion, perhaps more than dams of other soil types. Internal erosion washes out fine-grained particles from the filling material; the erosion occurs within the material itself or at an interface to another dam zone, depending on the mode of initiation. Whether or not internal erosion proceeds depend on the adequacy of the filter material. If internal erosion is allowed, it may manifest itself as sinkholes on the crest, increased leakage and muddy seepage once it surfaces, which here is called surfacing internal erosion (i.e. internal erosion in the excessive erosion or continuation phase). In spite of significant developments since the 1980s in the field of internal erosion assessment, the validity of methods developed by others on broadly graded materials are still less clear because most available criteria are based on tests of narrowly graded granular soils. This thesis specifically addresses dams that are composed of broadly graded glacial soils and investigates typical indicators, signs and behaviors of internal erosion prone dams. Based on a review of 90+ existing moraine core dams, which are located mainly in Scandinavia as well as North America and Australia/New Zealand, this thesis will show that not only the filter’s coarseness needs to be reviewed when assessing the potential for internal erosion to surface (i.e., erosion in the excessive or continuing phase); in addition, the grading stability of the filter and the core material as well as non-homogeneities that are caused by filter segregation need to be studied. Cross-referencing between these aspects improves the assessment of potential for internal erosion in dams of broadly graded soils and furthermore it provides aid-to-judgment. / QC 20100715

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