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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.
61

[pt] ANÁLISE DOS RECALQUES DE UM ATERRO SOBRE SOLOS MUITO MOLES DA BARRA DA TIJUCA – RJ / [en] SETTLEMENT ANALYSIS OF AN EMBANKMENT ON VERY SOFT SOIL IN BARRA DA TIJUCA

19 March 2013 (has links)
[pt] um depósito de solos muito moles da Barra da Tijuca (Baixada de Jacarepaguá), que pertence a uma planície costeira do Rio de Janeiro (RJ). O perfil de solos muito moles de fundação possuía até 17 m de espessura, caracterizados pelo Nspt igual a 0. O aterro foi construído em etapas e os recalques foram acelerados com a instalação de drenos verticais pré-fabricados na fundação. A construção do aterro durou cerca de 1,5 ano e foi monitorada por meio de instrumentação geotécnica. Campanhas de ensaios de campo e laboratório foram realizadas para determinação das características geotécnicas dos solos. Dez amostras foram coletadas em dois furos verticais de duas localidades virgens do depósito. Para evitar o amolgamento, cada etapa do processo de amostragem, desde a coleta até a moldagem dos corpos de prova, foi conduzida tomando-se cuidados especiais. Os corpos de prova foram moldados nas condições indeformada (horizontal e vertical) e completamente amolgada. Os procedimentos de moldagem dos corpos de prova foram associados à excelente qualidade da maioria dos corpos de prova moldados e por isso foram descritos detalhadamente. Todas as conclusões do trabalho levaram em consideração apenas os resultados dos ensaios realizados com corpos de prova considerados de excelente qualidade. Os ensaios de campo foram realizados em furos adjacentes aos furos onde foram coletadas as amostras indeformadas e na mesma região em que foram instalados grupos de instrumentos geotécnicos. A análise dos resultados dos ensaios de campo e laboratório e dos registros da instrumentação revela a existência de dois horizontes de solos muito moles que exibem características distintas e são separados por uma lente de areia contínua. O solo do horizonte superior (até 5 m de profundidade), que provavelmente foi formado após um período geológico de descarregamento do horizonte inferior, é caracterizado pelas condições de baixas tensões efetivas. O solo do horizonte inferior também está sob baixas tensões efetivas, contudo com uma tensão de préadensamento caracterizada pela diferença sp - sv0 25 kPa (constante com a profundidade), a qual pode ser associada ao mecanismo de carregamento e descarregamento mecânico. Uma correlação entre OCR (obtidas em ensaios de adensamento) e a razão Su/s’v0 (obtidas de ensaios de palheta e CPTu) foi atualizada para os solos do depósito. A alta compressibilidade dos solos foi confirmada pelos dados da instrumentação do aterro que mostraram recalques superficiais da ordem de 50 por cento da espessura do aterro (4,5 m). Os valores de Ca/Cc para os solos do depósito foram superiores aos valores característicos da maioria dos solos que se tem registro. Relações práticas para descrever a permeabilidade dos solos foram atualizadas. Os coeficientes de adensamento dos solos foram determinados por diversas formas e os resultados dos mesmos, apesar de apresentarem grande variabilidade (até dez vezes), não mostraram tendência quando os valores de campo (ensaios e dados de instrumentação) e laboratório foram comparados. O amolgamento dos corpos de prova afetou as características de permeabilidade e compressibilidade (primária e secundária) dos solos de ambos horizontes, mas os efeitos do mesmo foram mais severos nos solos do horizonte inferior. Uma previsão numérica, na qual se adotou um modelo para solo mole com fluência e foram considerados os parâmetros de laboratório, superestimaram levemente os recalques do aterro com o tempo. / [en] This work presents a settlement analysis of an embankment built on a very soft soil deposit in Barra da Tijuca (Baixada de Jacarepaguá), which is located in Rio de Janeiro’s coast. The geotechnical profile shows a very soft soil with thickness reaching 17 m, with Nspt equal 0. The embankment was built in stages and its settlements were accelerated with prefabricated drains. The construction lasted about 1,5 year and was monitored by means geotechnical instrumentation. Field and laboratory test programs were carried out to define the geotechnical characteristics of the soil. Ten samples were collected from two vertical boreholes before any loading was applied to the soil. To avoid disturbance, each stage of sample process, from sampling to specimen preparation, was conducted with special procedures. Tests have been carried out both in undisturbed (vertical and horizontal directions) and completely disturbed conditions. The specimen preparation procedures are described in detail. Conclusions considered only the results of tests conducted on specimens with excellent quality. The in-situ tests were performed in vertical boreholes next to boreholes where the undisturbed samples were collected and in the same location in which geotechnical instruments group were installed. The analysis of the field and laboratory tests and instrumentation data revealed the existence of two very soft soil layers exhibiting distinct characteristics which are separated by a continuous sand lens. The upper soil layer (from surface down to about 5 m depth), that was probably formed after an unloading geological period of the underlying layer, is characterized by low effective in situ stresses. The underlying soil is also under low in-situ effective stresses, but with a preconsolidation pressure characterized by the difference s’p - s’v0 25 kPa (constant with depth). A correlation between OCR (from consolidation tests) and Su/sv0 ratio (from vane and CPTU tests) for similar soils has been updated. The high compressibility of soils was confirmed by the embankment instrumentation data. Ca/Cc values, higher than usual for most known soils, were found. Practical relationships have been updated to describe the permeability of the deposit. Soil consolidation coefficients were estimated in different ways and values, even though have showed large difference (up to ten times), did not showed tendency when laboratory or field (tests and instrumentation data) values were compared. Disturbance affected the permeability and compressibility (primary and secondary) characteristic of the soils of both layers, but its effects were more severe in the underlying layer. A numerical prediction, in which a creep-soft-soil model was used and parameters obtained from the laboratory tests were considered, lightly overestimated the embankment settlements with time.
62

[pt] ESTUDO SOBRE RECALQUES EM CAMADA DE SOLO MOLE SUBMETIDA A 18 ANOS DE COMPRESSÃO UNIDIMENSIONAL: O CASO TERRA ENCANTADA / [en] SETTLEMENT STUDY ON A SOFT SOIL LAYER UNDER 18 YEARS OF ONE-DIMENSIONAL CONSOLIDATION: THE TERRA ENCANTADA CASE

19 February 2016 (has links)
[pt] O objetivo do presente trabalho é estudar a compressibilidade de um aterro de grandes dimensões construído há 18 anos na Barra da Tijuca (Rio de Janeiro) sobre de solo extremamente mole com aproximadamente 4 metros de espessura, onde foram observados recalques pós-construtivos de grande magnitude. A espessura constante do aterro e pouca variabilidade de espessura da camada mole envolvida permitem assumir condições de compressão próximas da unidimensional. Para o estudo, foi instalada instrumentação para medição de recalques por nivelamento geométrico de precisão. Um procedimento específico foi desenvolvido para possibilitar a medição de baixíssimas variações no desnível. Esse acompanhamento transcorreu por um período de 21 meses e mostrou que o aterro lançado 18 anos atrás continua em compressão. Foi realizada, também, uma campanha de ensaios de campo, contemplando CPTu (piezocone), dissipação e palheta, ensaios de caracterização completa em laboratório, incluindo ensaios químicos e mineralógicos, e ensaios oedométricos de longa duração em amostras indeformadas tipo Shelby. Por fim, com base em todas essas informações, procurou-se estimar os recalques ainda por ocorrer, especulando, ao final, sobre o tempo necessário para a estabilização dos recalques. / [en] The aim of this work is to study the compressibility of a large dimension embankment built 18 years ago at Barra da Tijuca (Rio de Janeiro) over a layer of extremely soft soil with thickness of about 4 meters, where large post-constructive settlements were observed. The constant thickness of the embankment and the low variability of the soft soil thickness allow one dimensional condition to be assumed. Geotechnical instrumentation has been installed for monitoring settlements by optical levelling. A specific procedure has been developed which allows measurement of very small settlement changes. Monitoring took place over 21 months and showed that the embankment built 18 years ago is still settling. Field tests have been carried out comprising CPTu with dissipation, vane shear test. Characterization tests, including chemical and mineralogical, and oedometric consolidation long term tests on undisturbed Shelby tube samples have also been carried out. Based on the collected data, an attempt at forecasting future settlements has been carried out including speculations about the time needed for the stabilization of the settlements.
63

Rockfalls from rock cuts beside Swedish railroads : A full scale fieldtest, to investigate rockfalls and how rock bounces

Thorbjörnson Lind, Thomas January 2016 (has links)
Rockfalls is a major problem around the world, if they occur in populated areas, they can cause major damage to infrastructure, injure or kill people. For this reason, it is important to be able to predict where the risk of rockfalls and how to prevent and protect populated areas from them. However, it is no easy task to predict rockfalls. Although if an area with potential area for rockfall is localized it may seem easy to construct protective meshing or bolting potential blocks down. But in many cases this is not easy to do due to practical issues or economic reasons, for example in rock cuts on older railways in Sweden. Fall heights from rock cuts like that are not particularly high but the risk of damage to the trains and infrastructure in the track area is high, however, it is unknown how extensive the damage may be. Trafikverket, the Swedish authority responsible for Sweden's roads and railways, has for some years investigated a new method for classifying and minimize the risk of rockfalls from rock cuts next to the railways. This study include aims to include the potential maximum distance of a block from the rockfall can travel to the existing method. This master's work is part of the investigation and will include full scale field test where the rockfalls are examined by filming them and then evaluate the “bounce coefficient”, coefficient of restitution, from the individual rockfalls using photogrammetric methods. During the field study, a geotechnical testing equipment, DCP test rig, to be evaluated for its ability of an easy way in the field to produce an estimated value on the coefficient of restitution. During the evaluation, two rockfall simulating software be used to investigate how well the results from them match the true blocks movements. / Stenras är ett stort problem runtom i världen, om de inträffar i bebyggda områden kan de leda till stora skador på infrastruktur, skador eller dödsfall. Av den anledningen är det viktigt att kunna förutse vart det finns risk för stenras och hur man kan förebygga dem och skydda bebyggda områden från dem. Dock är det ingen lätt uppgift att förutse stenras. Även om det finns ett potentiellt område för stenras kan det tyckas lätt att placera ut skyddsnät eller bulta fast potentiella block. Men i många fall är detta inte praktiskt, eller ekonomiskt, till exempel i bergsskärningar på äldre järnvägar i Sverige. Fallhöjderna här är inte speciellt höga men risken för skador på tåg och infrastruktur i spårområdet är hög, dock är det okänt hur omfattande skadorna kan bli. Trafikverket, den svenska myndigheten som ansvarar för Sveriges vägar och järnvägar, har under flera år utrett en ny metod för att klassificera och minimera riskerna för stenras från bergskärningar bredvid järnvägar. Denna utredning syftar bland annat till att till att väga in det potentiella maximalt avstånd ett block från stenras kan färdas i den befintliga modellen. Det här mastersarbetet är en del i den utredningen och kommer att innefatta ett fullskaligt fältförsök där stenras undersöks genom att de filmas och sedan utvärderas studskoefficienten, coefficient of restitution, från de enskilda rasen i stereo. Under fältstudien kommer en geoteknisk testutrustning, DCP test rigg, att utvärderas för sin förmåga att lätt i fält få fram ett uppskattat värde på studskoefficienten. Under utvärderingen kommer två stenrassimuleringsprogram att användas för att undersöka hur väl de stämmer med de verkliga blockens rörelser.
64

Dynamic amplification for moving vehicle loads on buried pipes : Evaluation of field-tests

Smagina, Zana January 2001 (has links)
No description available.
65

2D-model of a portal frame railway bridge for dynamic analysis

Kylén, Joakim January 2010 (has links)
No description available.
66

Response of Skewed Composite Adjacent Box Beam Bridge to Live and Environmental Load Conditions

Mutashar, Rana O. 24 September 2020 (has links)
No description available.
67

[pt] RECALQUES DO DEPÓSITO DE SOLOS MOLES DE CAMBOINHAS, RJ / [en] SETTLEMENTS OF THE SOFT SOILS DEPOSIT CAMBOINHAS, RJ

FERNANDO DUARTE AZEVEDO 28 October 2015 (has links)
[pt] O acompanhamento dos recalques de aterros, por meio de nivelamento topográfico periódico, permite estimar a evolução dos mesmos, bem como retroanalisar os parâmetros adotados em determinado projeto. Neste trabalho, recalques foram medidos em um aterro experimental sobre um depósito com 12 m de espessura de solos moles em Camboinhas, Niteroi (RJ), construído entre o final de 1977 e o início de 1978. O aterro serviu como modelo em escala real para a realização de estudos geotécnicos diversos na PUC-Rio, auxiliando o projeto de um empreendimento imobiliário da época. A obra foi embargada pouco tempo após seu início e, desde então, nenhum empreendimento foi realizado. Em 2013, novas amostras Shelby foram extraídas, para a realização dos ensaios de laboratório desta pesquisa. Ensaios de campo também foram realizados. Verificou-se que os recalques causados pela construção do aterro ainda estão ocorrendo, 37 anos após sua execução. Compararam-se, também, os valores de OCR de laboratório com os obtidos por meio de correlações empíricas com os resultados de campo. Por fim, foram feitas previsões da evolução do recalque médio com o tempo e da magnitude do valor total médio. / [en] Monitoring of embankment settlements using periodic topographic leveling allows one to preview their evolution, and to assess the parameters used in a specific design. In this research, settlements of an experimental embankment constructed between the end of 1977 and the beginning of 1978, over a 12 m thick soft soils deposit in Camboinhas, Niteroi (RJ), were monitored. At that time, the embankment served as large model to help designing of a commercial housing development. The work was hampered shortly after the end of embankment s construction and, since then, no enterprise was held. In 2013, in this research, new Shelby samples were obtained in order to carry out series of laboratory tests. Settlements due to the embankment construction were noted to be still progressing. Also, OCR values from laboratory tests were compared to those empirically evaluated from field results. Finally, the magnitude of total settlement and its progress with time were estimated.
68

Remediation of per- and polyfluoroalkyl substances (PFAS) in contaminated water by sorption to pine- and spruce bark

Ayranci Dahlberg, Rebecka January 2023 (has links)
PFAS are anthropogenic substances used in many different industrial operations and products because of their unique properties. Due to their negative impact on human health and environmental bioaccumulative characteristics different authorities have addressed the issue. In Sweden the limit is4 ng/L for four different PFAS in drinking water. Another risk to human health is elevated concentrations of toxic elements, causing Sweden to include them in the drinking water regulations withlimits such as 5 µg/L for arsenic, 25 µg/L for chromium and 5 µg/L for lead.This study is a continuation of an investigation for PFAS remediation in contaminated water by sorption to pine and spruce bark. The earlier study was a laboratory scale and implied that pine and spruce have some sorption capacity for long-chain PFAS. In this study pine and spruce bark were used as sorbent at an industrial site. The analysis was performed by weak-anion exchange extraction followed bysupercritical fluid chromatography coupled with a tandem mass spectrometer (SFC-MS/MS) and liquid chromatography coupled with tandem mass spectrometer (LC-MS/MS) for instrumental analyses of target ultra-short-chain PFAS, short- and long chain PFAS and branched PFOS isomers. An elemental analysis was executed with inductively coupled plasma mass spectrometry. The obtained results indicated removal for certain long-chain PFAS, potential for sorption of a specific ultra-short-chain PFAS and the elemental analysis implied some reduction of the chromium concentrations.
69

Comparative Analysis and Development of Receivers for Drone Remote Identification / Jämförande analys och utveckling av mottagare för fjärridentifiering av drönare

Guo, Xiaolinglong January 2023 (has links)
Similar to a car’s license plate, the European Union Aviation Safety Agency (EASA) has released new regulations imposing the registration of drone operators and the broadcasting of the drone’s “digital license plate”, i.e., the drone Remote Identification (RID) in flight, which gives a new opportunity in drone surveillance. Thus, it is meaningful to test the performance of Direct Remote Identification (DRI). To evaluate whether DRI can further improve the performance of the current Counter-Unmanned Aerial System (CUAS), it is essential to understand the performance of DRI, e.g., the effective region (maximal range). In this project, the field test of DRI reception with two broadcast protocols, Wireless Fidelity (Wi‑Fi) and Bluetooth, is carried out. As a result, with a 10dB high-gain receiving antenna and Mavic 3 as the transmitter in suburban areas, the maximal range can reach 1300 meters and still performs well in urban areas with a 700-meter maximal range when predicted with empirical propagation models. The field test results regard DRI signal as a helpful assistant in drone detection and surveillance. Therefore, a DRI receiver is developed in this project. All the basic functions like signal receiving and processing, Internet connection, and data transmission are successfully implemented. With further developments, the receiver could become a product that provides drone detection and tracking services. / Liknande en bils registreringsskylt har Europeiska unionens byrå för luftfartssäkerhet (EASA) infört nya regler som kräver registrering av drönaroperatörer och sändning av drönarens ”digitala registreringsskylt”, det vill säga fjärridentifiering (RID) under flygning, vilket ger nya möjligheter inom drönarövervakning. Därför är det meningsfullt att testa prestandan för Direkt Fjärridentifiering (DRI). För att utvärdera om DRI kan förbättra prestandan för det nuvarande systemet för bekämpning av obemannade luftfarkoster (CUAS), är det väsentligt att förstå DRIs prestanda, till exempel den effektiva regionen (maximal räckvidd). I detta projekt genomförs fälttest av DRI-mottagning med två sändningsprotokoll, Wireless Fidelity (Wi-Fi) och Bluetooth. Som resultat, med en 10dB högvinstantenn och Mavic 3 som sändare i förortsområden, kan maximal räckvidd nå 1300 meter och presterar fortfarande bra i urbana områden med en maximal räckvidd på 700 meter när det förutsägs med empiriska propagationsmodeller. Fälttestresultaten betraktar DRI-signalen som en hjälpsam assistent i drönardetektion och övervakning. Därför utvecklas en DRI-mottagare i detta projekt. Alla grundläggande funktioner som signal mottagning och bearbetning, internetanslutning och datatransmission är framgångsrikt implementerade. Med ytterligare utvecklingar kan mottagaren bli en produkt som tillhandahåller tjänster för detektering och spårning av drönare.
70

Sambandet mellan andlighet och utbrändhet - en jämförande studie av beroendebehandlare i kriminal- och beroendevård

Hultén Sandeheim, Jonna January 2011 (has links)
Religiositet och andlighet tycks ha samband med fysisk och psykisk hälsa. I uppsatsen undersöks sambandet mellan andlighet och utbrändhet, två grupper behandlare jämförs och mätegenskaper hos skalorna Spirituality, Religiousness and Personal Beliefs Field-Test Instrument (WHOQOL-SRPB), Spiritual Involvement and Beliefs Scale (SIBS), Maslach Burnout Inventory – Human Service Survey (MBI-HSS) och Utbrändhet i arbetet (UA) undersöks. Studiedeltagarna var 38 programledare för kriminalvårdens tolvstegsprogram och 39 behandlare i ett psykoterapinätverk inom beroendevården (svarsfrekvens 61,5%). Andlighet korrelerade med personlig prestation (personal accomplishment; r = 0,315, p < 0,05). I beroendevården fanns ett samband mellan hög grad av andlighet/religiositet och högre grad av utbrändhet. Studien visar att andlighet skulle kunna ge ökat självförtroende, och genom detta påverka hälsa och allmänt välbefinnande samt att effekten av andlighet/religiositet verkar vara positiv i andliga/religiösa sammanhang men inte i mer sekulariserade miljöer. Slutligen konstateras att validiteten hos utbrändhetsmåtten kan ifrågasättas och att vidare utveckling av andlighetsmåtten bör ske.

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