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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.
11

Virus and Virus-sized Particle Transport in Variable-aperture Dolomite Rock Fractures

Mondal, Pulin Kumar 18 December 2012 (has links)
In this thesis a study of the factors affecting virus and virus-sized particle transport in discrete fractured dolomite rocks is presented. Physical and chemical characteristics of two fractured rocks were determined, including fracture aperture distribution, rock matrix porosity, mineral composition, and surface charge. Hydraulic and transport tests were conducted in the fractures with a conservative solute (bromide) and carboxylate-modified latex (CML) microspheres of three sizes (20, 200, and 500 nm in diameter). The earlier arrival of larger microspheres as compared to bromide indicated the effects of pore-size exclusion and preferential flow paths in the fractures. The tailing of the bromide and the smaller microsphere (20 nm) in the breakthrough curves (BTC) indicated the diffusive mass transfer between the mobile water (flowing) and immobile water (stagnant water in the low aperture areas and porous rock matrix). The effects of ionic strength and cation type on the transport of viruses (bacteriophages MS2 and PR772) and virus-sized microspheres (20 and 200 nm) were determined from the transport tests in a fracture at three levels of ionic strength (3, 5, and 12 mM) and composition (containing Na+ and/or Ca2+ ions). Retention of the microspheres and bacteriophages increased with increasing ionic strength. The addition of divalent ions (Ca2+) influenced the retention to a greater extent than monovalent ions (Na+). The effects of the aperture distribution variability, matrix diffusion, and specific discharge on the solute and microsphere transport were determined from the transport tests conducted in two fractures. The higher variability in the aperture distribution contributed to higher solute dispersion, and flow channeling as evident from the breakthrough curves for individual spatially distributed outlets. A three-dimensional model simulation of the bromide transport with varying matrix porosity identified that the porous matrix influenced the solute transport. In the transport tests, retention of the microspheres decreased with increasing specific discharge in both fractures. The results of this research have helped in identifying the important factors and their effects on solute, virus, and virus-sized colloid transport in fractured dolomite rocks, which can be useful in determining the risk of pathogen contamination of water supplies in fractured dolomite rock aquifers.
12

Effects Of Geometrical Factors On Fracture Toughness Using Semi-circular Bending Type Specimens

Het, Kivanc 01 February 2008 (has links) (PDF)
Semi-circular specimens (SCB) under three point-bending which are commonly used for fracture testing of rocks were used here for fracture mechanics tests. A total of 65 specimens were tested by using Ankara andesite rock. Investigations including the effects of initial notch thickness, different loading span ratios (S/R), flattened loading end, and little dimensional variations when preparing the specimens were carried out. Stress intensity factors for specimens with different geometries were computed individually by using a 3D finite element program ABAQUS. Specimens with a preliminary notch thickness varying from 0.84 to 3.66 mm were tested under three point bending. For a second group of specimens loading span was changed and fracture toughness variation was studied. Another change in the specimen geometry was made by machining a flat loading end at the upper load application point. Fracture toughness values were computed using the stress intensity values computed from numerical modeling and failure loads from the experiments. It was found that up to 2 mm fracture toughness was not affected by variations in the thickness of preliminary notches. Fracture toughness was not affected by changing the loading span. For specimens with flat loading ends, fracture toughness was about 16% lower than the value found from regular SCB type specimens loaded at a point at the top by a steel roller. As a result of about 46 experiments average fracture toughness of Ankara G&ouml / lbasi andesite was found as 1.36 MPa .
13

Shear Mode Rock Fracture Toughness Determination With A Circular Plate Type Specimen Under Three-point Bending

Sener Karakas, Sinem 01 March 2011 (has links) (PDF)
Fracture toughness is an important rock property for rock fracturing and fragmentation applications. Theory and practice of opening mode (mode I) and shearing mode (mode II) fracture toughness tests are still in a developing stage for the cylindrical rock cores. A new circular plate type test specimen is used for mode II fracture toughness testing on rock cores. This involves a straight edge notched circular plate type core disc geometry under three-point bending load / new method and its associated specimen geometry is referred as straight edge notched disc bend (SNDB) specimen under three-point bending. Mode II fracture toughness results of the tests with this new geometry were compared to the results of the tests commonly employed for mode II fracture toughness testing. Specimen geometries were modeled and mode II stress intensity factors were computed by finite element modeling using ABAQUS program. For comparison purposes, mode II or shearing mode fracture toughness KIIc of two different rock types were determined by different testing methods commonly employed in recent practice. Core specimens of Ankara andesite and Afyon marble rock types were tested with cracked chevron notched Brazilian disc and cracked straight through Brazilian disc specimens under Brazilian type loading, semi-circular bend specimen and straight edge notched disc bending specimen geometries under three-point bending.For all testing groups, cylindrical cores with diameters varying from 7.5 cm to 12.5 cm were prepared with notch lengths changing from 1.5 cm to 2.6 cm. Effect of specimen thickness on mode II fracture toughness was investigated for three different testing methods. Fracture toughness values remained constant when thickness of the specimens was increased for cracked straight through Brazilian disc, semi-circular bend and straight notched disc bend methods. For cracked straight through Brazilian disc method KIIc values of Ankara andesite and Afyon marble were 0.99 MPa&radic / m and 0.86 MPa&radic / m, respectively. Mode II fracture toughness with semi-circular bend specimen was 0.43 MPa&radic / m for andesite and 0.46 MPa&radic / m for marble. When the results of the two three-point bending type tests were compared straight notched disc under three-point bending resulted in higher KIIc values (0.61 MPa&radic / m for andesite and 0.62 MPa&radic / m for marble) than the results found by semi-circular bend tests.
14

Virus and Virus-sized Particle Transport in Variable-aperture Dolomite Rock Fractures

Mondal, Pulin Kumar 18 December 2012 (has links)
In this thesis a study of the factors affecting virus and virus-sized particle transport in discrete fractured dolomite rocks is presented. Physical and chemical characteristics of two fractured rocks were determined, including fracture aperture distribution, rock matrix porosity, mineral composition, and surface charge. Hydraulic and transport tests were conducted in the fractures with a conservative solute (bromide) and carboxylate-modified latex (CML) microspheres of three sizes (20, 200, and 500 nm in diameter). The earlier arrival of larger microspheres as compared to bromide indicated the effects of pore-size exclusion and preferential flow paths in the fractures. The tailing of the bromide and the smaller microsphere (20 nm) in the breakthrough curves (BTC) indicated the diffusive mass transfer between the mobile water (flowing) and immobile water (stagnant water in the low aperture areas and porous rock matrix). The effects of ionic strength and cation type on the transport of viruses (bacteriophages MS2 and PR772) and virus-sized microspheres (20 and 200 nm) were determined from the transport tests in a fracture at three levels of ionic strength (3, 5, and 12 mM) and composition (containing Na+ and/or Ca2+ ions). Retention of the microspheres and bacteriophages increased with increasing ionic strength. The addition of divalent ions (Ca2+) influenced the retention to a greater extent than monovalent ions (Na+). The effects of the aperture distribution variability, matrix diffusion, and specific discharge on the solute and microsphere transport were determined from the transport tests conducted in two fractures. The higher variability in the aperture distribution contributed to higher solute dispersion, and flow channeling as evident from the breakthrough curves for individual spatially distributed outlets. A three-dimensional model simulation of the bromide transport with varying matrix porosity identified that the porous matrix influenced the solute transport. In the transport tests, retention of the microspheres decreased with increasing specific discharge in both fractures. The results of this research have helped in identifying the important factors and their effects on solute, virus, and virus-sized colloid transport in fractured dolomite rocks, which can be useful in determining the risk of pathogen contamination of water supplies in fractured dolomite rock aquifers.
15

Rock cutting by abrasive water jet: an energy approach / Corte de rocha com jato d\'água abrasivo: uma abordagem baseada em energia

Arab, Paola Bruno 20 March 2017 (has links)
Abrasive waterjet (AWJ) cutting is a versatile technique which has been effectively applied to rock cutting since the late 1980s. The complexity of the interaction between the waterjet and the rocks complicates the thorough understanding of the phenomena involved in AWJ rock cutting. On one hand, rocks are complex materials which are generated through different processes in an uncontrolled environment without human interference. On the other hand, the AWJ acts with high velocity and turbulence, complicating direct observation and the perception of details. In this respect, the present research aims to contribute to the study of AWJ cutting applied to rocks, including the analysis of qualitative and quantitative information, both of great importance regarding the study of complex materials. Concerning quantitative data, special attention is given to the investigation of the cutting efficiency, which can be analyzed by observing conditions in which the higher cutting rate is associated with the minimum energy provided by the AWJ machine per removed volume of rock. Moreover, the real efficiency can be analyzed through the investigation of the conditions in which the major part of the energy provided by the AWJ machine is used effectively for rock cutting, deducting dissipation losses. The effects of varying traverse velocity and pump pressure on cutting parameters were also investigated, in addition to the influence of rock properties on the effective energy of cutting. The effective energy was calculated based both on the specific energy and specific destruction work of the materials. With respect to the qualitative investigation, petrographic and scanning electron microscopy (SEM) analyses were conducted in order to visualize and better understand the different effects of cutting on the studied rocks. Cutting tests with a traverse velocity of 200 mm/min and a pump pressure of 400 MPa presented the most efficient rock cutting regarding both methods of efficiency analysis. Dry density and tensile strength presented fair correlations with the effective cutting energy, while the modulus ratio presented the best correlations. It was observed that brittleness plays a key role in the understanding of the phenomena involved in AWJ rock cutting. / O jato d\'água abrasivo (AWJ) é uma técnica versátil que tem sido efetivamente aplicada ao corte de rochas desde o fim da década de 1980. A complexidade da interação entre o jato e as rochas dificulta a compreensão detalhada dos fenômenos envolvidos no corte de rochas com AWJ. Por um lado, rochas são materiais complexos gerados em ambientes sem interferência humana. Por outro lado, o AWJ age com alta velocidade e turbulência, dificultando a observação direta do procedimento. Assim, a presente tese de doutorado visa a contribuir com o estudo do corte de rochas com AWJ, incluindo análises de dados qualitativos e quantitativos, ambos de grande importância em estudos de materiais complexos. A análise quantitativa possui foco na investigação da eficiência de corte, a qual pode ser analisada por meio da observação das condições em que há a maior taxa de corte associada à mínima energia fornecida pelo AWJ por volume de rocha removido. Além disso, a eficiência real do corte pode ser analisada a partir da investigação das condições em que a maior parte da energia fornecida pelo AWJ é usada para efetivamente cortar a rocha, descontando perdas por dissipação. Os efeitos da variação da velocidade transversal de corte e da pressão da bomba nos parâmetros de corte também foram investigados, além da influência das propriedades das rochas na energia efetiva de corte. A energia efetiva de corte, denominada energia relativa de formação da ranhura (EKR), foi calculada com base na energia específica e no trabalho de destruição específico dos materiais. Análises de microscopia eletrônica de varredura (SEM) e petrografia foram conduzidas para visualizar e compreender melhor os diferentes efeitos do corte nas rochas estudadas. Os testes de corte realizados com velocidade transversal do bocal de 200 mm/min e pressão da bomba de 400 MPa apresentaram as melhores eficiências de corte considerando-se ambos os métodos de análise de eficiência. Dentre as propriedades das rochas investigadas, a massa específica e a resistência à tração por compressão diametral apresentaram correlações razoáveis com EKR, enquanto que o modulus ratio apresentou as melhores correlações. Observou-se que a ruptibilidade possui papel fundamental na compreensão dos fenômenos envolvidos no corte de rochas com AWJ.
16

Development Of Specimen Geometries For Mode I Fracture Toughness Testing With Disc Type Rock Specimens

Alkilicgil, Cigdem 01 June 2010 (has links) (PDF)
Flattened Brazilian disc and modified ring test methods are attractive methods being simpler compared to the other mode I fracture toughness testing methods on rock cores. The aim of this study is to improve these simple methods to yield fracture toughness values that are close to the ones determined by the suggested methods. ABAQUS finite element program was used to determine stress intensity factors of models with various dimensions. Comparing fracture toughness to the results obtained by semicircular bending method tests (0.94 MPa&amp / #8730 / m for andesite and 0.56 MPa&amp / #8730 / m for marble) and the cracked chevron notched Brazilian disc method tests (1.45 MPa&amp / #8730 / m for andesite and 1.08 MPa&amp / #8730 / m for marble), proper geometrical parameters were investigated by changing diameter, central-hole diameter, and loading angle of Ankara andesite and Afyon marble specimens. Semicircular bending method results were lower than the cracked chevron notched Brazilian disc method results. With flattened Brazilian disc method, the closest results (1.45 MPa&amp / #8730 / m for andesite and 1.12 MPa&amp / #8730 / m for marble) to the suggested method was obtained by 54 mm diameter discs with loading angles between 32.5&deg / and 38.0&deg / and with thicknesses between 19 mm and 34 mm. With modified ring test on andesite, the closest results to the suggested method was obtained by 75 mm diameter discs with 8 mm central-hole diameter and 25&deg / loading angle (1.47 MPa&amp / #8730 / m for andesite and 1.07 MPa&amp / #8730 / m for marble), and with 14 mm central-hole diameter and 16&deg / loading angle (1.50 MPa&amp / #8730 / m for andesite and 1.05 MPa&amp / #8730 / m for marble).
17

Investigating the Influence of Mechanical anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological Repositories

Lisjak Bradley, Andrea 10 January 2014 (has links)
Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the underground openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was used in combination with new field measurements from the Mont Terri underground research laboratory. The response of Opalinus Clay during the excavation of a full-scale emplacement (FE) test tunnel was characterized by geodetic monitoring of wall displacements, radial extensometers and longitudinal inclinometers. The deformation measurements indicated strong directionality induced by the combined effect of in situ stress field and presence of bedding planes striking parallel to the tunnel axis, with the most severe deformation occurring in the direction approximately perpendicular to the material layering. Computer simulations were conducted using a newly-extended combined finite-discrete element method (FEM/DEM), a numerical technique which allows the explicit simulation of brittle fracturing and associated seismicity. The numerical experimentation firstly focused on the laboratory-scale analysis of failure processes (e.g., acoustic activity) in brittle rocks, and on the role of strength and modulus anisotropy in the failure behaviour of Opalinus Clay in tension and compression. The fracturing behaviour of unsupported circular excavations in laminated rock masses was then analyzed under different in situ stress conditions. Lastly, the modelling methodology was applied to the aforementioned FE tunnel to obtain original insights into the possible EDZ formation process around emplacement tunnels for nuclear waste. The calibrated numerical model suggested delamination along bedding planes and subsequent extensional fracturing as key mechanisms of the damage process potentially leading to buckling and spalling phenomena. Overall, the research findings may have a potential impact on the constructability and support design of an underground repository as well as implications for its long-term safety assessment procedure.
18

Investigating the Influence of Mechanical anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological Repositories

Lisjak Bradley, Andrea 10 January 2014 (has links)
Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the underground openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was used in combination with new field measurements from the Mont Terri underground research laboratory. The response of Opalinus Clay during the excavation of a full-scale emplacement (FE) test tunnel was characterized by geodetic monitoring of wall displacements, radial extensometers and longitudinal inclinometers. The deformation measurements indicated strong directionality induced by the combined effect of in situ stress field and presence of bedding planes striking parallel to the tunnel axis, with the most severe deformation occurring in the direction approximately perpendicular to the material layering. Computer simulations were conducted using a newly-extended combined finite-discrete element method (FEM/DEM), a numerical technique which allows the explicit simulation of brittle fracturing and associated seismicity. The numerical experimentation firstly focused on the laboratory-scale analysis of failure processes (e.g., acoustic activity) in brittle rocks, and on the role of strength and modulus anisotropy in the failure behaviour of Opalinus Clay in tension and compression. The fracturing behaviour of unsupported circular excavations in laminated rock masses was then analyzed under different in situ stress conditions. Lastly, the modelling methodology was applied to the aforementioned FE tunnel to obtain original insights into the possible EDZ formation process around emplacement tunnels for nuclear waste. The calibrated numerical model suggested delamination along bedding planes and subsequent extensional fracturing as key mechanisms of the damage process potentially leading to buckling and spalling phenomena. Overall, the research findings may have a potential impact on the constructability and support design of an underground repository as well as implications for its long-term safety assessment procedure.
19

A 3D hydro-mechanical discrete element model for hydraulic fracturing in naturally fractured rock / Un modèle hydro-mécanique 3D d'élément discret pour la fracturation hydraulique de roches naturellement fracturées

Papachristos, Efthymios 08 February 2017 (has links)
La fracturation hydraulique est au cœur d'un certain nombre de phénomènes naturels et induits et est cruciale pour un développement durable de la production de ressources énergétiques. Compte tenu de son rôle crucial, ce phénomène a été pris en compte au cours des trois dernières décennies par le monde académique. Néanmoins, un certain nombre d'aspects très importants de ce processus ont été systématiquement négligés par la communauté. Deux des plus remarquables sont l'incapacité de la grande majorité des modèles existants à aborder la propagation des fractures hydrauliques dans les massifs rocheux fracturés où l'injection de fluide peut à la fois conduire à la fracturation de la roche intacte et à la réactivation de fractures préexistantes. Un autre aspect essentiel de ce processus est qu'il est intrinsèquement tridimensionnel, ce qui est souvent négligé par les modèles actuellement disponibles. Pour aborder ce problème essentiel, un modèle hydro-mécanique couplé basé sur la méthode des éléments discrets a été développé. La masse rocheuse est ici représentée par un ensemble d'éléments discrets interagissant à travers des lois de contact cohésifs qui peuvent se casser pour former des fissures à l'intérieur du milieu simulé. Ces fissures peuvent se coalescer pour former des fractures. Une méthode de volume fini est utilisée pour simuler l'écoulement de fluide entre les éléments discrets. L'écoulement est calculé en fonction de la déformation de l'espace poreux dans le milieu intact et de l'ouverture des fissures dans les fractures. De plus, les fractures naturelles sont modélisées explicitement de sorte qu'elles peuvent présentées des comportements mécanique et hydraulique différents de ceux de la matrice rocheuse intacte. La simulation des processus de fracturation hydraulique dans un milieu initialement intact en considérant plusieurs points d'injection plus ou moins espacés a permis de mettre en évidence l'évolution spatio-temporelle des fractures hydrauliques et de quantifier l'impact des différentes stratégies d'injection sur des indices représentatifs du volume fracturé, de l'intensité et de la densité des fractures ou encore sur la pression de fluide au niveau du puits. De plus, l'injection dans une fente de perforation non alignée sur le plan de contrainte minimum a génère des fractures hydrauliques non planaires percolantes si la connectivité est faible, ce qui peut être gênant pour la mise en place du proppant. En outre, des interactions fortes prennent place entre des fractures hydrauliques étroitement espacées ont été mises en évidence grâce au le suivi de la orientation de contrainte principale locale et ont révélé l'importance des effets d'ombre de contrainte. Des solutions sont proposées pour optimiser les traitements multiples à partir d'un puits de forage non parfaitement aligné. Enfin, l'interaction entre une seule fracture hydraulique et une seule fracture naturelle de propriétés et d'orientations variables a été étudiée à l'aide du modèle proposé. L'évolution de la fracture hydraulique et la réponse globale de l'échantillon ont été enregistrées d'une manière comparable aux données expérimentales existantes pour établir un pont entre les résultats expérimentaux et numériques. Les fractures naturelles persistantes semblent être des barrières pour la fracture hydraulique si leur conductance est élevée par apport a celle de la matrice ou si leur raideur est faible par rapport a la rigidité du milieu environnant. D'autre part, une faible rigidité dans les discontinuités non persistantes pourrait provoquer une bifurcation de la fracture hydraulique principale. De plus, des angles d'approche élevés et des contraintes différentielles fortes semblent favoriser le croisement de la fracture naturelle alors que des angles faibles engendrent plutôt un glissement ou une dilatation par cisaillement de la partie du plan qui n'est pas affectée par la perturbation de la contrainte. / Hydraulic fracturing is at the core of a number of naturally occurring and induced phenomena and crucial for a sustainable development of energy resource production. Given its crucial role this process has been given increasing attention in the last three decades from the academic world. Nonetheless a number of very significant aspects of this process have been systematically overlooked by the community. Two of the most notable ones are the inability of the vast majority of existing models to tackle at once the propagation of hydraulic fractures in realistic, fractured rocks-masses where hydraulic fracturing is a competing dipole mechanism between fracturing of the intact rock and re-activation of exiting fracture networks. Another essential aspect of this process is that it is intrinsically three-dimensional which is neglected by most models. To tackle this vital problem taking into account these pivotal aspects, a fully coupled hydro-mechanical model based on the discrete element method has been developed. The rock mass is here represented by a set of discrete elements interacting through elastic-brittle bonds that can break to form cracks inside the simulated medium. Theses cracks can coalesce to form fractures. A finite volume scheme is used to simulate the fluid flow in between these discrete elements. The flow is computed as a function of the pore space deformation in the intact medium and of the cracks' aperture in the fractures. Furthermore, the natural fractures are modelled explicitly and present mechanical and hydraulic properties different from the rock matrix. Employing this model in an intact numerical specimen, single fluid injection and multiple closely spaced sequential injections, enabled the description the full spatio-temporal evolution of HF propagation and its impact on quantitative indexes used in description of hydraulic fracturing treatments, such as fractured volume, fracture intensity and down-the-hole pressure for different control parameters and in-situ stress-fields. Moreover, injections from perforation slots which are not well aligned to the minimum stress plane showed possible creation of percolating non-planar hydraulic fractures of low connectivity, which can be troublesome for proppant placement. Also, strong interactions between closely spaced HF were highlighted by tracking the local principal stress rotation around the injection zones, emphasizing the importance of stress shadow effects. Optimization solutions are proposed for multiple treatments from a non-perfectly aligned wellbore. Finally, interaction between a single hydraulic fracture and a single natural fracture of varying properties and orientations was studied using the proposed model. The evolution of the hydraulic fracture and the global response of the specimen were recorded in a way comparable to existing experimental data to bridge the experimental and numerical findings. Persistent natural fractures appeared to be barriers for the hydraulic fracture if their conductance is high compared to the matrix conductivity or if their stiffness is significantly low compared to the rock matrix rigidity. Low stiffness in non-persistent defects might also cause a bifurcation of the main hydraulic fracture due to the local stress field perturbation around the defect and ahead of the hydraulic fracture tip. Furthermore, high approach angles and differential stresses seemed to favour crossing of the natural fracture while low angles enable shear slippage or dilation on the part of the plane which is not affected by the local stress perturbation.
20

Rock cutting by abrasive water jet: an energy approach / Corte de rocha com jato d\'água abrasivo: uma abordagem baseada em energia

Paola Bruno Arab 20 March 2017 (has links)
Abrasive waterjet (AWJ) cutting is a versatile technique which has been effectively applied to rock cutting since the late 1980s. The complexity of the interaction between the waterjet and the rocks complicates the thorough understanding of the phenomena involved in AWJ rock cutting. On one hand, rocks are complex materials which are generated through different processes in an uncontrolled environment without human interference. On the other hand, the AWJ acts with high velocity and turbulence, complicating direct observation and the perception of details. In this respect, the present research aims to contribute to the study of AWJ cutting applied to rocks, including the analysis of qualitative and quantitative information, both of great importance regarding the study of complex materials. Concerning quantitative data, special attention is given to the investigation of the cutting efficiency, which can be analyzed by observing conditions in which the higher cutting rate is associated with the minimum energy provided by the AWJ machine per removed volume of rock. Moreover, the real efficiency can be analyzed through the investigation of the conditions in which the major part of the energy provided by the AWJ machine is used effectively for rock cutting, deducting dissipation losses. The effects of varying traverse velocity and pump pressure on cutting parameters were also investigated, in addition to the influence of rock properties on the effective energy of cutting. The effective energy was calculated based both on the specific energy and specific destruction work of the materials. With respect to the qualitative investigation, petrographic and scanning electron microscopy (SEM) analyses were conducted in order to visualize and better understand the different effects of cutting on the studied rocks. Cutting tests with a traverse velocity of 200 mm/min and a pump pressure of 400 MPa presented the most efficient rock cutting regarding both methods of efficiency analysis. Dry density and tensile strength presented fair correlations with the effective cutting energy, while the modulus ratio presented the best correlations. It was observed that brittleness plays a key role in the understanding of the phenomena involved in AWJ rock cutting. / O jato d\'água abrasivo (AWJ) é uma técnica versátil que tem sido efetivamente aplicada ao corte de rochas desde o fim da década de 1980. A complexidade da interação entre o jato e as rochas dificulta a compreensão detalhada dos fenômenos envolvidos no corte de rochas com AWJ. Por um lado, rochas são materiais complexos gerados em ambientes sem interferência humana. Por outro lado, o AWJ age com alta velocidade e turbulência, dificultando a observação direta do procedimento. Assim, a presente tese de doutorado visa a contribuir com o estudo do corte de rochas com AWJ, incluindo análises de dados qualitativos e quantitativos, ambos de grande importância em estudos de materiais complexos. A análise quantitativa possui foco na investigação da eficiência de corte, a qual pode ser analisada por meio da observação das condições em que há a maior taxa de corte associada à mínima energia fornecida pelo AWJ por volume de rocha removido. Além disso, a eficiência real do corte pode ser analisada a partir da investigação das condições em que a maior parte da energia fornecida pelo AWJ é usada para efetivamente cortar a rocha, descontando perdas por dissipação. Os efeitos da variação da velocidade transversal de corte e da pressão da bomba nos parâmetros de corte também foram investigados, além da influência das propriedades das rochas na energia efetiva de corte. A energia efetiva de corte, denominada energia relativa de formação da ranhura (EKR), foi calculada com base na energia específica e no trabalho de destruição específico dos materiais. Análises de microscopia eletrônica de varredura (SEM) e petrografia foram conduzidas para visualizar e compreender melhor os diferentes efeitos do corte nas rochas estudadas. Os testes de corte realizados com velocidade transversal do bocal de 200 mm/min e pressão da bomba de 400 MPa apresentaram as melhores eficiências de corte considerando-se ambos os métodos de análise de eficiência. Dentre as propriedades das rochas investigadas, a massa específica e a resistência à tração por compressão diametral apresentaram correlações razoáveis com EKR, enquanto que o modulus ratio apresentou as melhores correlações. Observou-se que a ruptibilidade possui papel fundamental na compreensão dos fenômenos envolvidos no corte de rochas com AWJ.

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