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Showing 1 to 4 of 4 (0.101 seconds)Spelling suggestions: "subject:"modulus off deformation"" "subject:"modulus oof deformation""
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Numerical Validation and Refinement of Empirical Rock Mass Modulus EstimationHUME, COLIN DAVID 21 September 2011 (has links)
A sound understanding of rock mass characteristics is critical for the engineering prediction of tunnel stability and deformation both during construction and post-excavation. The rock mass modulus of deformation is a necessary input parameter for many numerical analysis methods to describe the constitutive behavior of a rock mass. Tests for determining this parameter directly by in situ test methods are inherently difficult, time consuming and expensive, and these challenges are more problematic when dealing with tunnels in weaker, softer rock masses where errors in modulus (stiffness) estimation have a profound impact on closure predictions. In addition, rock masses with modest structure can be candidate sites for highly sensitive structures such as nuclear waste repository tunnels. For these generally stiffer rock masses, the correct modulus assessment is essential for prediction of thermal response during the service life of the tunnel.
Numerous empirical relationships based on rock mass classification schemes have been developed to determine rock mass deformation modulus in response to these issues. The empirical relationship provided by Hoek & Diederichs (2006) based on Geological Strength Index (GSI) has been determined from a database of in situ test data describing a wide range of rock masses with GSI values greater than 25 and less than 80. Within this range of applications there is a large variation in measured values compared to the predicted relationship and predictive uncertainty at low GSI values. In this research, a practical range of rock mass quality, as defined by GSI, including "Blocky\Disturbed\Seamy" rock masses, "Very Blocky" and relatively competent rock masses are analyzed using discretely fractured numerical models. In particular the focus is on tunnel response. Tunnel closure in these simulations is compared to predictions based on modulus estimates. The proposed refinement to the Generalized Hoek-Diederichs relationship is made on the basis of these simulations for tunnelling applications. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2011-09-20 22:34:06.642
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Influência dos Agregados Graúdos da Região de Goiânia no Módulo de Deformação Tangente Inicial do Concreto / Influence of coarse aggregate in the region of Goiânia Initial Tangent Modulus of Deformation of ConcreteBARBOSA, Isa Lorena Silva 24 November 2009 (has links)
Made available in DSpace on 2014-07-29T15:03:40Z (GMT). No. of bitstreams: 1
Dissertacao Isa Lorena.pdf: 2675574 bytes, checksum: 324410a337fb201f2446d151678a3e01 (MD5)
Previous issue date: 2009-11-24 / This research is carried out to study the influence of aggregate source on the initial tangent
modulus of deformation of concrete (Eci), to correlate the resistance to compression (fc) with
the module Eci and compare the results of this research with the equations proposed by
international standards and the Brazilian.
To this end, it was used three levels of resistance to 28 days: 20MPa, 30Mpa and 40Mpa and
ranged up the aggregate source in the types lithological micaschist, Granulito and Basalt. Set
the type of cement, sand, water, and additive content of mortar. All materials are used in
dosages of Goiânia and the surrounding region in order to determine the behavior of these
materials in concrete that is produced in the region.
The experimental program of this research is divided into two parts. The first is to determine
the curves of strength of each aggregate source test of resistance to compression in the age of
three, seven and 28 days, while the second part determines the initial tangent modulus of
deformation on the ages of seven and 28 days.
For the first part of the experimental program were molded 54 body-of-evidence and tested
for resistance to compression. For the second part was molded 90 body-of-evidence, where 36
were tested for resistance to compression and 54 with the initial tangent modulus of
deformation. With the end of testing was performed a statistical analysis of results obtained
through software STATISTIC.
In the analysis it was the influence of aggregate source in the initial tangent modulus of
deformation (Eci), noting influences the levels of resistance adopted and distinct variations in
the influence of aggregate source studied on the Eci, by increasing order of the results of
module: micaschist, granulito and basalt.
The results also indicated that the NBR 6118 (ABNT, 2003) overestimates the values of
modulus of deformation of concrete. / Esta pesquisa desenvolve-se para estudar a influência do agregado graúdo sobre o módulo de
deformação tangente inicial do concreto (Eci), correlacionar a resistência à compressão (fc)
com o módulo Eci e comparar os resultados desta pesquisa com as equações propostas pelas
normas internacionais e pela brasileira.
Para esse fim, utilizaram-se três níveis de resistência aos 28 dias: 20MPa, 30Mpa e 40Mpa e
variou-se o agregado graúdo nos tipos litológicos Micaxisto, Granulito e Basalto. Fixou o tipo
de cimento, areia, água, aditivo e teor de argamassa. Todos os materiais utilizados nas
dosagens são da região de Goiânia e entorno com o objetivo de determinar o comportamento
desses materiais nos concretos que são produzidos na região.
O programa experimental desta pesquisa é dividido em duas partes. A primeira visa
determinar as curvas de dosagem de cada agregado graúdo através de ensaios de resistência à
compressão nas idades de três, sete e 28 dias, enquanto que a segunda parte determina o
módulo de deformação tangente inicial nas idades de sete e 28 dias.
Para a primeira parte do programa experimental foram moldados 54 corpos-de-prova e todos
ensaiados à resistência à compressão. Para a segunda parte foram moldados 90 corpos-deprova,
onde 36 foram ensaiados à resistência à compressão e 54 com o módulo de deformação
tangente inicial. Com o termino dos ensaios foi realizado uma análise estatística dos
resultados obtidos através do software STATISTIC.
Com a análise constatou-se a influência do agregado graúdo sobre o módulo de deformação
tangente inicial (Eci), observando sucintas influências dos níveis de resistências adotados e
distintas variações na influência dos agregados graúdos estudados sobre o Eci, apresentando
em ordem crescente dos resultados do módulo: micaxisto, granulito e basalto.
Os resultados também indicaram que a NBR 6118 (ABNT, 2003) superestima os valores do
módulo de deformação dos concretos. Com os resultados encontrados para cada agregado
graúdo foi possível encontrar as relações entre os resultados da equação proposta pela NBR
6118 (ABNT, 2003) e ACI (ACI, 1999) além de estimar os valores do módulo de elasticidade
de acordo com os tipos litológicos estudados por essa pesquisa.
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Gesteinsmechanische Versuche und petrophysikalische Untersuchungen – Laborergebnisse und numerische SimulationenBaumgarten, Lars 26 May 2016 (has links) (PDF)
Dreiaxiale Druckprüfungen können als Einstufenversuche, als Mehrstufenversuche oder als Versuche mit kontinuierlichen Bruchzuständen ausgeführt werden. Bei der Anwendung der Mehrstufentechnik ergeben sich insbesondere Fragestellungen hinsichtlich der richtigen Wahl des Umschaltpunktes und des optimalen Verlaufs des Spannungspfades zwischen den einzelnen Versuchsstufen. Fraglich beim Versuch mit kontinuierlichen Bruchzuständen bleibt, ob im Versuchsverlauf tatsächlich Spannungszustände erfasst werden, welche die Höchstfestigkeit des untersuchten Materials repräsentieren. Die Dissertation greift diese Fragestellungen auf, ermöglicht den Einstieg in die beschriebene Thematik und schafft die Voraussetzungen, die zur Lösung der aufgeführten Problemstellungen notwendig sind. Auf der Grundlage einer umfangreichen Datenbasis gesteinsmechanischer und petrophysikalischer Kennwerte wurde ein numerisches Modell entwickelt, welches das Spannungs-Verformungs-, Festigkeits- und Bruchverhalten eines Sandsteins im direkten Zug- und im einaxialen Druckversuch sowie in dreiaxialen Druckprüfungen zufriedenstellend wiedergibt. Das Festigkeitsverhalten des entwickelten Modells wurde in Mehrstufentests mit unterschiedlichen Spannungspfaden analysiert und mit den entsprechenden Laborbefunden verglichen.
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Gesteinsmechanische Versuche und petrophysikalische Untersuchungen – Laborergebnisse und numerische SimulationenBaumgarten, Lars 25 November 2015 (has links)
Dreiaxiale Druckprüfungen können als Einstufenversuche, als Mehrstufenversuche oder als Versuche mit kontinuierlichen Bruchzuständen ausgeführt werden. Bei der Anwendung der Mehrstufentechnik ergeben sich insbesondere Fragestellungen hinsichtlich der richtigen Wahl des Umschaltpunktes und des optimalen Verlaufs des Spannungspfades zwischen den einzelnen Versuchsstufen. Fraglich beim Versuch mit kontinuierlichen Bruchzuständen bleibt, ob im Versuchsverlauf tatsächlich Spannungszustände erfasst werden, welche die Höchstfestigkeit des untersuchten Materials repräsentieren. Die Dissertation greift diese Fragestellungen auf, ermöglicht den Einstieg in die beschriebene Thematik und schafft die Voraussetzungen, die zur Lösung der aufgeführten Problemstellungen notwendig sind. Auf der Grundlage einer umfangreichen Datenbasis gesteinsmechanischer und petrophysikalischer Kennwerte wurde ein numerisches Modell entwickelt, welches das Spannungs-Verformungs-, Festigkeits- und Bruchverhalten eines Sandsteins im direkten Zug- und im einaxialen Druckversuch sowie in dreiaxialen Druckprüfungen zufriedenstellend wiedergibt. Das Festigkeitsverhalten des entwickelten Modells wurde in Mehrstufentests mit unterschiedlichen Spannungspfaden analysiert und mit den entsprechenden Laborbefunden verglichen.
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