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An experimental study of the validity of the round panel test method for shotcreteEl zain, Nadia January 2018 (has links)
Shotcrete (sprayed concrete) was used for the first time in 1914 and has become of growing importance in stabilizing the excavated tunnel sections over the past century. Even though the technology develops, there are some difficult tasks such as the design of a bolt anchored tunnel lining made of shotcrete. A proven and established design method does not exist today; instead the design of tunnel linings are based on trial and error or experience from similar projects. One method used today, to determine the actual structural behavior of fiber reinforced shotcrete, is the standard beam test method. Previous studies have shown that the beam method gives scattered results since the testing volume are relatively small and the fibers might be unevenly distributed. In 1998, an alternative to determine the actual structural behavior of reinforced shotcrete was proposed, based on using round determinate panels. In 2004 this method became a part of the American Society for Testing and Materials, ASTM, standards. The method has the potential of becoming a major, reliable test procedure that better reproduce the behavior of reinforced shotcrete in situ, compared to test beams. An experimental test series was performed to compare the different testing methods in terms of data variability and validity, in the laboratory of Vattenfall in Älvkarleby. The experiment was performed on 30 specimens in total, with five different concrete recipes. The difference in the recipe was the fiber and cement content. The round panels are designed according to ASTM C-1550 and the beams according to SS-EN14488-3. The results from the experiment is here presented and evaluated, and also including the data variability and validity for the proposed method. The two basic testing methods of using beams and round panels are investigated, compared and evaluated, and their advantages and disadvantages discussed. / Sprutbetong användes första gången år 1914 och har under det gångna århundradet blivit allt viktigare för att stabilisera utsprängda tunnelsektioner. Trots att tekniken utvecklas finns det svårigheter med att exempelvis utforma bultförankrade tunnelbeklädnader av sprutbetong. En beprövad och etablerad metod att konstruera sprutbetongbeklädnad existerar inte idag. Istället används erfarenhetsåterföring från tidigare projekt och/eller experimentella försök. En testmetod som används idag för att återskapa beteendet hos sprutbetong är balkförsök. Tidigare studier har däremot visat att resultaten från försöken oftast har stor spridning vilket kan bero på att brottytorna är små areor där fibrerna kan vara ojämnt fördelade vilket påverkar resultaten. År 1998 föreslogs en alternativ metod för att fastställa de mekaniska egenskaperna hos sprutbetong, baserat på användning av runda plattor. År 2004 blev denna metod en del av the American Society for Testing and Materials, ASTM, standarder. Metoden har potential att bli en viktigt och tillförlitligt testmetod som mer realistiskt efterliknar beteendet hos fiberarmerad sprutbetong jämfört med balkprovning. En experimentell försöksserie har genomförts hos Vattenfall i Älvkarleby, för att jämföra de två metoderna med avseende på mätosäkerhet. Försöksserien är på totalt 30 prover, där fem olika betongrecept använts. Cementmängden och fiberhalten varierade mellan de olika recepten. De runda plattorna är utförda enligt ASTM C-1550 och balkarna enligt SS-EN14488-3. Resultaten från försöken har redovisats och utvärderats, och en mätosäkerhersanalys presenteras för metoden ASTM C-1550. Korrelationen mellan resultaten från de två metoderna är beräknad och varianskoefficienten presenteras. För- och nackdelar mellan båda testmetoderna diskuteras.
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[pt] COMPORTAMENTO MECÂNICO E CONTROLE DE QUALIDADE DO CONCRETO PROJETADO COM FIBRAS NO REVESTIMENTO DE TÚNEIS DA MINA CUIABÁ / [en] MECHANICAL BEHAVIOUR AND QUALITY CONTROL OF THE FIBER REINFORCED SHOTCRETE APPLIED AS ROCK SUPPORT AT THE CUIABA MINE EXCAVATIONVITOR MOREIRA DE ALENCAR MONTEIRO 30 September 2020 (has links)
[pt] O presente trabalho investigou o comportamento mecânico do concreto projetado com fibras aplicado nas escavações da mina Cuiabá e o seu controle tecnológico através do ensaio de duplo puncionamento. Para essa pesquisa utilizouse o traço desenvolvido pelos engenheiros da mina Cuiabá com dois tipos diferentes de fibra sintética e uma fibra de aço. Inicialmente, caracterizou-se o material compósito através de ensaios de flexão em prismas (EN 14651) e de arrancamento. Em seguida, os resultados obtidos foram utilizados em conjunto com os ensaios de flexão em painéis circulares (ASTM C1550), quadrados (EN 14488-5) e de larga escala para o dimensionamento do sistema de suporte utilizado na mina Cuiabá. As frações mais baixas de fibras sintéticas são mais indicadas nos locais onde a qualidade da rocha é razoável ou boa, enquanto as fibras de aço podem ser aplicadas onde a qualidade do maciço rochoso é classificada como muito fraca. Em relação ao controle tecnológico do concreto com fibras, os ensaios de duplo puncionamento realizados em máquinas mais rígidas são mais eficientes em diminuir a extensão da
instabilidade pós-fissuração, limitar os erros nas correlações com os ensaios de flexão (EN 14651) e em reduzir a variação das propriedades mecânicas do material. A aplicação do ensaio de duplo puncionamento com controle fechado pela corrente extensométrica foi o método mais efetivo em limitar a instabilidade pós-fissuração independente da máquina de ensaios selecionada. / [en] The present work investigated the mechanical behavior of the fiber reinforced shotcrete applied at the Cuiabá mine excavation and its quality control through the double punch test. For this research, the mix composition was developed by Cuiabá mine Engineers with the addition of two different types of synthetic fibers and one steel fiber. Firstly, the cement based composite was studied at the material level through bending (EN 14651) and pullout tests. Thereafter, the support system of the Cuiabá mine excavation was designed based on round (ASTM C1550), square (EN 14488-5) and large scale panel tests. The application of lower synthetic fiber volume fractions was more suited for the areas with good quality rock indexes,
while steel fibers were better suited at field with lower rock classes. Regarding the quality control of FRC, the double punch tests that were conducted in stiffer testing machines were more effective in reducing the post-peak instability, in limiting the errors in the correlations with bending tests (EN 14651) and in reducing the mechanical properties variations of the material. Finally, the application of the double punch test with closed-loop control of the circumferential extensometer turned to be the most effective method in limiting the post-peak instability regardless of the selected machine.
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Nové směry provádění hydroizolací dopravních podzemních staveb / New directions for waterproofing of underground transportČech, Tomáš January 2019 (has links)
This diploma thesis focuses on the implementation of waterproofing of underground constructions using an LLDPE membrane hinged on anchors. In the future, this method will replace the commonly used waterproofing system in Scandinavia with extruded polyethylene foam. This method of tunnel construction and waterproofing is compared with the NRTM method, often used in Central Europe. The thesis describes the installation of a waterproofing system, especially materials, accessories, welding devices and auxiliary installation equipment. The main focus of the thesis is to verify the reliability of the individual types of welds and to assess the waterproofing system in terms of implementation and environmental demands.
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Nové směry provádění hydroizolací dopravních podzemních staveb / New directions for waterproofing of underground transportČech, Tomáš January 2019 (has links)
This diploma thesis focuses on the implementation of waterproofing of underground constructions using an LLDPE membrane hinged on anchors. In the future, this method will replace the commonly used waterproofing system in Scandinavia with extruded polyethylene foam. This method of tunnel construction and waterproofing is compared with the NRTM method, often used in Central Europe. The thesis describes the installation of a waterproofing system, especially materials, accessories, welding devices and auxiliary installation equipment. The main focus of the thesis is to verify the reliability of the individual types of welds and to assess the waterproofing system in terms of implementation and environmental demands.
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Návrh sekundárního městského kolektoru s důrazem na ochranu před průnikem podzemní vody / Design of the secondary city utility tunnel with an emphasis on protection against ingress of groundwaterVrána, Tomáš January 2015 (has links)
In the first part, the master’s thesis deals with the history of utility tunnels, methods of construction processes and materials from which they are built. It also mentions methods and materials which protect against the effects of groundwater. The thesis is mainly dedicated to the design and structural design of the secondary utility tunnel lining with an emphasis on protection against ingress of groundwater. The mathematical model was created in Plaxis 2DAE software.
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Stavebně technologický projekt přístavby objektu Nejvyššího soudu ČR v Brně / Construction technology project of extension of the Supreme Court building in BrnoConík, Šimon Unknown Date (has links)
Theme of the diploma thesis is a construction technology project extension of the building of the Supreme Court of the Czech Republic in Brno. The content of the diploma thesis is the study of the main technological stages of the main building, solution of wider transport relations with a focus on building supply, objects schedule, time schedule of the main building. The work also includes the project of construction site equipment, design of the main construction machines and mechanisms, technological regulations for special foundations and rough construction, which are supplemented by control and test plans and a plan for securing material resources. As part of other assignments, As part of other assignments, I process occupational health and safety, ecology and environmental protection for selected construction processes, itemized budget for special foundation and rough construction
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Městský okruh Blanka, tunel Královská obora - ražená část, stavebně technologická příprava stavby / City circle road Blanka, tunnel Královská obora - mined section, preparation and building construction technologyKobielusz, Petr January 2013 (has links)
My thesis is focused on process preparation and building construction technology of primary lining road tunnel, implemented in city part of Troja in the capital city Prague. Specifically it is a part of tunnel complex Blanka. The name of this part is Kralovská obora. If the all tunnel parts are built this tunnel complex Blanka can be complemented to already opened tunnels Zlíchovský, Mrázovka and Strahovský which are the part of city traffic circle. This technology preparation includes schedules and financial plans of the building, technological prescription for the primary tunnel lining, safety plan, control and trial/test plans, environmental plan, project of construction site, design of the main working machines, items budget of the north tunnel tube, coordination situation plan with wider relationships transport routes and technical report of building technological project.
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Problematika testování stříkaných betonů / The Issue of testing shotcreteŠkapová, Pavla January 2014 (has links)
The master‘s thesis focuses on testing the shotcrete prepared in laboratory conditions. The main observed properties are compresive strenght of shotcrete and modulus of elasticity. The aim is assessment of methods for measuring those parameters. The calibrating correlations for strenght characteristics of shotcrete are given by obtaining the results of used methods. The shotcrete composition, amount and type of accelerating additive as well as economic aspect of using shotcrete is also assessed.
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