Academic literature on the topic 'Cam Clay'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Cam Clay.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Cam Clay"
1
Muhamad Bustaman, Nurul Wahieda, and Mohd Salman Abu Mansor. "A Study on CAD/CAM Application in CNC Milling Using Industrial Clay." Applied Mechanics and Materials 761 (May 2015): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amm.761.32.
Full textAbstract:
Throughout the production process, improper planning and exploitation of the CAD/CAM system leads to the low level utilization of the CNC milling machine. In product design, tangible prototype is fabricated using CAD/CAM techniques in the design phase to analyse and modify the product before actual production. In this research, industrial clay is used as the prototype material. The objectives of the study are to investigate the machining parameters of industrial clay using the CNC milling machine and to apply the CAD/CAM system in producing a clay sample part via the CNC milling machine. Using uncomplicated and low cost setup for the fabrication method, an industrial clay sample part is prepared in the CAD/CAM system and shaped using the CNC milling machine. The difference between the simulated and the actual machining time of the machined part is analysed.
2
Liu, M. D., and J. P. Carter. "A structured Cam Clay model." Canadian Geotechnical Journal 39, no. 6 (December 1, 2002): 1313–32. http://dx.doi.org/10.1139/t02-069.
Full textAbstract:
A theoretical study of the behaviour of structured soil is presented. A new model, referred to as the Structured Cam Clay model, is formulated by introducing the influence of soil structure into the Modified Cam Clay model. The proposed model is hierarchical, i.e., it is identical to the Modified Cam Clay soil model if a soil has no structure or if its structure is removed by loading. Three new parameters describing the effects of soil structure are introduced, and the results of a parametric study are also presented. The proposed model has been used to predict the behaviour of structured soils in both compression and shearing tests. By making comparisons of predictions with experimental data and by conducting the parametric study it is demonstrated that the new model provides satisfactory qualitative and quantitative modelling of many important features of the behaviour of structured soils.Key words: calcareous soils, clays, fabric, structure, constitutive relations, plasticity.
3
MAšíN, D. "Hypoplastic Cam-clay model." Géotechnique 62, no. 6 (June 2012): 549–53. http://dx.doi.org/10.1680/geot.11.t.019.
Full text
4
Srinivasa Murthy, B. R., A. Vatsala, and T. S. Nagaraj. "Revised Cam‐Clay Model." Journal of Geotechnical Engineering 117, no. 6 (June 1991): 851–71. http://dx.doi.org/10.1061/(asce)0733-9410(1991)117:6(851).
Full text
5
Graham, J., N. Tanaka, T. Crilly, and M. Alfaro. "Modified Cam-Clay modelling of temperature effects in clays." Canadian Geotechnical Journal 38, no. 3 (June 1, 2001): 608–21. http://dx.doi.org/10.1139/t00-125.
Full textAbstract:
The Cam-Clay model for isothermal mechanical behaviour of clays has been extended to take account of the effects of temperature on stressstrain behaviour. The assumptions used in constructing the new model are based on published results and on new data presented in the paper. The model allows prediction of how heating and cooling affect volume changes, pore-water pressures, and strengths for both normally consolidated and overconsolidated saturated clays. It permits modelling of observed reductions in the overconsolidation ratio with increasing temperature. The model provides accessible qualitative explanations for temperature effects that were previously difficult to understand. It will also allow easy implementation for quantitative modelling in triaxial stress fields. Results predicted by the model are compared with data collected by the authors at temperatures up to 100°C. The model does not account for changes that occur in clay minerals at higher temperatures, for example, in bentonites at temperatures higher than about 150°C.Key words: clay, triaxial, temperature, modelling, elasticplastic, Cam-Clay.
6
Xu, Bin Bin, and Toshihiro Noda. "Determination of Parameter in SYS Cam-Clay Model of Ultra-Soft Clay." Applied Mechanics and Materials 744-746 (March 2015): 470–73. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.470.
Full textAbstract:
Parameter analyses in the constitutive model determine the precision of numerical results. Cam-clay model is the first elasto-plastic model in the world and widely used in the practical engineering. SYS Cam-clay model is proposed based on Cam-clay model by incorporating the concept of overconsolidation, soil structure and anisotropy. There are two groups of parameters in this model, elasto-plastic parameters that are exactly same as those in Cam-clay model and evolutional parameters that decide the variation of overconsolidation, soil structure and anisotropy. The detailed process to determine the parameters is introduced step by step.
7
Murthy, B. R. Srinivasa, A. Vatsala, and T. S. Nagaraj. "Can Cam‐Clay Model Be Generalized?" Journal of Geotechnical Engineering 114, no. 5 (May 1988): 601–13. http://dx.doi.org/10.1061/(asce)0733-9410(1988)114:5(601).
Full text
8
Karstunen, Minna, and Mirva Koskinen. "Plastic anisotropy of soft reconstituted clays." Canadian Geotechnical Journal 45, no. 3 (March 2008): 314–28. http://dx.doi.org/10.1139/t07-073.
Full textAbstract:
The aim of the paper is to extend the experimental validation of the S-CLAY1 model, which is a recently proposed elastoplastic constitutive model that accounts for initial and plastic strain-induced anisotropy. Drained stress path controlled tests were performed on reconstituted samples of four Finnish clays to study the effects of anisotropy in the absence of the complexities of structure present in natural undisturbed clays. Each test involved several loading, unloading, and reloading stages with different values of stress ratio and, hence, induced noticeable changes in the fabric anisotropy. Comparisons between test results and model predictions with the S-CLAY1 model and the modified Cam clay model demonstrate that despite its simplicity, the S-CLAY1 model can provide excellent predictions of the behaviour of unstructured soil.
9
Xu, Bin Bin, Toshihiro Noda, and Kentaro Nakai. "Sensitivity Analysis of Parameters in SYS Cam-Clay Model." Advanced Materials Research 1030-1032 (September 2014): 864–70. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.864.
Full textAbstract:
The SYS Cam-clay model, which is extended based on the Cam-clay model and the critical state theory, is able to describe the heavily overconsolidated and structure soils. However compared with Cam-clay model with five elasto-plastic parameters there are six additional evolutional parameters in SYS Cam-clay model and the sensitivity analysis of the new added parameters should be carried out. Through the calculation of constitutive response assuming the uniform deformation field, the sensitivities of degradation index of structure, degradation index of overconsolidation ratio and rotational hardening index are investigated respectively. It can be seen that the peak strength and the “rewinding behavior” in the effective stress path are influenced greatly while there is no coupling effect of these parameters mutually. The initial overconsolidation ratio and degree of structure also have an effect on the mechanical behavior and the initial specific volume.
10
Fattah, Mohammed Y., Firas A. Salman, and Bestun J. Nareeman. "Numerical Simulation of Triaxial Test in Clayey Soil Using Different Constitutive Relations." Advanced Materials Research 243-249 (May 2011): 2973–77. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2973.
Full textAbstract:
The stress paths to which specimens are subjected in triaxial tests together with the yield surfaces, which may be exercised in different models of such a test are simulated. A laboratory testing on undisturbed clay soil samples was performed in order to characterize the stress-strain behaviour of the residual soils in Sao Paulo sedimentary deposit. The sample is tested under isotropically consolidated drained triaxial compression. Strain controlled procedure was used to simulate stress-strain relationships of the soil. Seven models are used; namely: linear elastic, Duncan-Chang hyperbolic, Mohr-Coulomb, Cam clay, modified Cam clay, new Mohr-Coulomb and Cap model. It was concluded that the results of Cam clay and Duncan Chang models are the closest to the experimental data under low confining pressures; 49 and 98 kPa. Both models exhibit parabolic stress-strain relationships while the linear elastic model results are far away from experimental ones especially at large stress levels. At high confining pressure; 196 kPa, the modified Cam clay best correlates the stress and strain.
Dissertations / Theses on the topic "Cam Clay"
1
Tam, Heng-Kong. "Some applications of Cam-clay in numerical analysis." Thesis, City University London, 1992. http://openaccess.city.ac.uk/7885/.
Full textAbstract:
The research described in this thesis investigated some applications of Cam-clay in numerical analyses. Single element analysis using the program CASIS was conducted to model undrained and drained triaxial compression tests to investigate the relative importance of the critical state soil parameters and streis history on the calculated soil behaviour. The values of these parameters covered the range of most commonly occurring natural soils. The investigation was extended to finite element modelling of plate loading tests using the computer program CRISP to examine the relative importance of the critical state soil parameters and stress history on the calculated undrained plate-soil behaviour. The capability of finite element coupled consolidation analysis of boundary value problems was demonstrated by the simulation of laboratory hydraulic fracturing experiments. The effects of rate of cavity water pressure increase, bore size, confining pressure and overconsolidation ratio on fracturing pressures were examined. The results of the parametric study of triaxial compression tests and plate loading tests were quantified in terms of stiffness (or tangent modulus), strength (or bearing pressure) and strain (or settlement) at the initial, yield, peak and ultimate states in the stress-strain (or pressure-settlement) response and allowed the comparison of these quantities for changing values of the soil model parameters. The studies revealed that the parameter x/A was the most influential because the initial states of soil were dependent on the values of ic and A and this dependence affected the subsequent stress-strain behaviour. In the prediction of movements of soil structures, the parameters x, A and a' are the most influential and their values should be critically evaluated for input in numerical analyses. In prediction of stability, the values of x, A and M are the most important ones. The work showed that the hydraulic fracturing phenomenon can be modelled by finite element coupled consolidation analysis. The computer program CRISP was validated against closed-form solutions and was found to predict the hydraulic fracturing phenomenon with a reasonable. degree of accuracy when the results were compared with the experimental data obtained by Mhach (1991). It was found that the rate of cavity water pressure increase had a significant influence in the prediction of fracturing pressure. The confining pressure was an important factor whereas the effects of bore size and overconsolidation ratio had some effects but were not as significant as the first two.
2
Lodi, Paulo César. "Aplicação do modelo cam-clay modificado a um solo arenoso." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-23032007-151306/.
Full textAbstract:
O modelo cam-clay modificado foi aplicado aos resultados experimentais obtidos para um solo arenoso típico da cidade de São Carlos. Os ensaios de compressão triaxial foram conduzidos em equipamento moderno, com instrumentação interna, segundo distintas trajetórias de carregamento. Verificou-se que os resultados obtidos em termos de modelagem foram satisfatórios, principalmente quando a tensão octaédrica (p\') foi diminuida durante os carregamentos. Nesse caso, tanto em termos de modelagem como de resultados experimentais, houve expansão de volume do solo. Com o aumento da tensão octaédrica, verificou-se a ocorrência de compressão volumétrica do solo. Observou-se que o modelo apresenta uma previsão de deformações axiais maiores do que as observadas experimentalmente nas trajetórias de -30, -50, 30, 40, 50, 60, 120 graus e no ensaio triaxial convencional com \'sigma\' 3 = 100 kPa. Além disso, determinou-se a superfície inicial de plastificação do solo utilizando-se dois critérios que tenderam a fornecer valores de tensão de cedência aproximadamente iguais, notando-se que a condição de fluxo associado não é obedecida.The modified cam-clay model was used to model experimental results of a sandy soil from São Carlos - SP. Triaxial compression tests were performed using Bishop - Wesley cell with internal transducers to measure axial and radial strains. It was observed that the model fairly fitted experimental results, specially when medium effective stress (p\') is reduced during loading. In this case, both the model and the experimental results, showed volume increase. When (p\') increases the model and the tests showed a tendency to give volumetric compression, although the values were differents. The model yielded strains larger than that measured in the tests when the stress-paths were of -30, -50, 30, 40, 50, 60, 120 degrees and in axial compression test with 100 kPa of confining pressure. Besides that, initial yield surface of soil was calculated from test results using two different criteria which gave about the same yield stress and it is show that normality rule was not satisfied in this soil.
3
Nader, José Jorge. "Modelos elasto-plásticos para solos: o Cam-Clay e sua aplicação a diferentes trajetórias de tensão." Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-03042018-072402/.
Full textAbstract:
A deformação dos solos é, atualmente, objeto de intensas pesquisas em todo o mundo movidas pelas necessidades da engenharia geotécnica. Este trabalho, que aborda o tema nos aspectos teórico e experimental, inicia-se revendo as relações constitutivas elasto-plásticas e o modelo Cam-Clay, cuja formulação matemática é apresentada de um modo diferente do usual. O modelo é construído de forma sistêmica a partir das equações elasto-plásticas gerais. Na parte experimental investiga-se o comportamento de um solo siltoso remoldado, quando submetido a ensaios triaxiais com diferentes trajetórias de tensão após adensamento isotrópico. Por fim comparam-se resultados experimentais e teóricos. Conclui-se que o modelo comporta-se melhor nas trajetórias de tensão em que não há diminuição da tensão octaédrica, embora preveja deformações volumétricas exageradas. Por sua vez, nas trajetórias em que há diminuição da tensão octaédrica, a diferença entre o comportamento previsto e o observado é grande, revelando que o modelo não deve ser aplicado nesses casos.Soil deformation is today a subject of intense research all over the world motivated by the necessities of the geotechnical engineering. This work, which approaches the theme in both theoretical and experimental aspects, reviews the elastoplastic constitutive relations and the Cam-Clay model, and examines the behavior of a remoulded silty soil when subjected to different stress paths. Following a brief exposition of some basic Continuum Mechanics concepts, the elastic and elastoplastic constitutive equations are presented in a general form, which serve as a basis for several soil models. After a discussion about soil behavior and its representation by models, the Cam-Clay mathematical formulation is presented in an unusual form: it begins with the general elastoplastic constitutive equations, the elastic stress-strain relation, the yield function and the hardening law being given. The plastic stress-strain relation in deduced. In the experimental part the behavior of a remoulded silty soil from the Escola Politécnica Foundation Experimental Field is investigated. Oedometric, isotropic and triaxial compression tests (that were performed as part of the research) are described and analysed. Among them the triaxial tests with different stress paths after isotropic consolidation constitute the principal subject of analysis. Finally the Cam-Clay equations are integrated along the tests stress paths and the experimental e theoretical results are confronted. The conclusions is that the model behaves better in stress paths where there is no octabedral stress reduction, although even then it predicts exaggerated volumetric strains. In its turn, in stress paths where there is an octahedral stress reduction the difference between predicted and observed behavior is large, revealing that the model should not be applied in such cases.
4
Brulin, Jérôme. "Modélisation thermomécanique d'un creuset de haut fourneau." Thesis, Orléans, 2010. http://www.theses.fr/2010ORLE2047/document.
Full textAbstract:
Le creuset est une structure majoritairement composée de matériaux réfractaires destinés à supporter de fortes sollicitations thermomécaniques, dues au contact direct de ses parois internes avec la fonte à 1500°C. L’objectif de cette thèse est de développer un modèle thermomécanique de creuset capable de localiser les zones sensibles de la structure et d’estimer les contraintes. Des blocs de carbone, des structures maçonnées (briques avec mortier) et un pisé carboné sont les principaux constituants du creuset. Afin d’identifier leur comportement, des essais de caractérisation ont été développés pour des températures atteignant les 1500°C. Un modèle de type Cam-Clay modifié est proposé pour modéliser le comportement compactant du pisé. L’influence de la température et des fortes pressions est prise en compte. Une bonne corrélation est obtenue entre les résultats expérimentaux et numériques. Les structures maçonnées, en contact direct avec la fonte, sont fortement sollicitées, ce qui peut conduire à l’ouverture des joints de mortier. La modélisation proposée pour ces structures est basée sur une approche micro-macro où les briques et le mortier sont remplacés par un matériau homogène équivalent, et ce pour différents états d’ouverture de joints. La non-linéarité du comportement est reproduite grâce à un critère d’ouverture en contrainte, qui permet le passage d’un état à un autre. Les propriétés homogénéisées sont obtenues par homogénéisation périodique en s’appuyant sur une approche énergétique. La modélisation d’un essai de la littérature permet la validation du modèle. La modélisation finale du creuset est confrontée aux résultats de l’instrumentation d’un creuset. Une bonne concordance entre ces résultats est obtenueThe blast furnace hearth is mainly composed of refractory materials to support strong thermo-mechanical loads. Indeed, there is a direct contact between its internal walls and the molten pig iron at 1500°C. The objective of this thesis is to develop a thermo-mechanical model able to locate the sensitive areas and to estimate the stress fields. Carbon blocks, masonries (bricks and mortars) and a carbon ramming mix are the main constituents of the hearth. In order to identify their behaviours, characterization tests have been developed for temperatures up to 1500°C. A modified Cam-Clay model is proposed in order to reproduce the hardening behaviour of the ramming mix. The influences of temperature and pressure are taken into account. Experimental and numerical results are in good agreement. Masonries, submitted to high temperature gradients are highly stressed, which can lead to the opening of the mortar joints. The proposed masonry modelling is based on a micro-macro approach where bricks and mortars are replaced by an equivalent homogenous material for different joint states. The non-linearity of the behaviour is reproduced thanks to a stress criterion, allowing the transition from one state to another. Homogenized properties are obtained by periodic homogenization with an energetic approach. The modeling of a shear test available in the literature allows the validation of this model. The final modelling of a hearth is compared with in-situ instrumentation results. A good agreement is reached between these results
5
Arvelo, Jose. "ADAPTING THE MODIFIED CAM CLAY CONSTITUTIVE MODEL TO THE COMPUTATIONAL ANALYSIS OF DENSE GRANULAR SOILS." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2452.
Full textAbstract:
The computational constitutive Modified Cam Clay Model (MCCM) was developed at Cambridge to study the behavior of clays and has been proven to be effective. In this study, this model is extended to the case of dense sands to analyze the accuracy of the stress-strain behavior. This analysis is based on triaxial test data applied to remolded and compacted sand samples under drained conditions. The laboratory triaxial tests were performed by the Florida Department of Transportation to research the permeability effect in sandy soils compacted up to 95% of maximum unit weight at the optimum moisture content. Each soil sample was tested using different stress paths. In addition, these data were also used to obtain the soil parameters. These soil parameters are used as input data for the Modified Cam Clay Model. Moreover, a computer program in MATLAB was developed based on the MCCM constitutive theory and application in order to predict the stress-strain response for overconsolidated soils under drained condition. Based on observations of the qualitative behavior of these soils, a modification is proposed in this thesis to the original constitutive model to improve the predicted stress-strain behavior. The results of the computer program are typically presented in the deviatoric stress versus shear strain and the stress path plane (deviatoric stress versus mean effective stress). These are the principal plots used for the behavior prediction of soil specimens. Furthermore, the results of the computer program were compared to the laboratory triaxial test data. In general, it is may be concluded that, MCCM with some modification, is applicable to dense sands.M.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
6
Sánchez, Henríquez Felipe Ignacio. "Análisis numérico y experimental del método de consolidación por vacío para relaves integrales." Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/142659.
Full textAbstract:
Ingeniero CivilEl presente trabajo de título analiza el método de consolidación por vacío y su aplicabilidad para el mejoramiento de un relave integral. El estudio se basa en la comparación de resultados obtenidos a partir de un modelo experimental, modelaciones numéricas de elementos finitos y soluciones analíticas recopiladas de la literatura técnica. El modelo experimental aplica succión generada por una bomba de vacío sobre una columna de relave integral saturado y monitorea la evolución temporal de la deformación vertical, simulando la aplicación de esta técnica en suelos depositados en la cubeta de un tranque de relaves. Además, se realizan simulaciones numéricas de elementos finitos con el software Abaqus para reproducir las condiciones del modelo experimental y poder capturar las mediciones de laboratorio. El comportamiento elasto-plástico del material se simula con el modelo constitutivo Cam-Clay Modificado (MCCM). La calibración de los parámetros de compresibilidad y de conductividad hidráulica del material se realiza con ensayos de laboratorio considerando dos estados de depositación y otros parámetros se adoptan de los trabajos de Cifuentes y Verdugo (2007) y Conejera (2016). La aplicación de -80 kPa de vacío induce deformaciones verticales en la columna de relave integral que son equivalentes a las inducidas por la aplicación de 3,5 - 4 metros de material de relleno. El fenómeno de consolidación de vacíos se puede simular numéricamente con un software de elementos finitos y el uso de un modelo constitutivo elasto-plástico, como Cam-Clay Modificado (MCCM). Los parámetros críticos para modelar apropiadamente el fenómeno son los parámetros de compresibilidad y la conductividad hidráulica del material. Si bien estos parámetros se pueden estimar con ensayos estándares de laboratorio, se requieren algunos ajustes para estimar el asentamiento máximo y el tiempo de consolidación.
7
Ghahremannejad, Behrooz. "Thermo-Mechanical Behaviour of Two Reconstituted Clays." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/492.
Full textAbstract:
The effect of temperature on soil behaviour has been the subject of many studies in recent years due to an increasing number of projects related to the application of high temperature to soil. One example is the construction of facilities for the disposal of hot high level nuclear waste canisters (150-200C) several hundred meters underground in the clay formations. Despite this, the effects and mechanism by which temperature affects the soil properties and behaviour are not fully known. A limited amount of reliable experimental data, technological difficulties and experimental methods employed by different researchers could have contributed to the uncertainties surrounding the soil behaviour at elevated temperature. Also several thermo-mechanical models have been developed for soil behaviour, but their validity needs to be examined by reliable experimental data. In this research, efforts have been made to improve the experimental techniques. Direct displacement measuring devices have been successfully used for the first time to measure axial and lateral displacements of clay samples during tests at various temperatures. The thermo mechanical behaviour of two reconstituted clays has been investigated by performing triaxial and permeability tests at elevated temperature. Undrained and drained triaxial tests were carried out on normally consolidated and over consolidated samples of M44 clay and Kaolin C1C under different effective stresses, and at temperatures between 22C and 100C. Permeability tests were carried out on samples of M44 clay at temperatures between 22C and 50C. The effects of temperature on permeability, volume change, pore pressure development, shear strength and stiffness, stress strain response and critical state parameters for different consolidation histories have been investigated by comparing the results at various temperatures. The results are also compared with the predictions of two models. It has been found that at elevated temperature the shear strength, friction angle and initial small strain stiffness reduce whereas permeability increases. The slope of the swelling line in the v-p� plane has been found to reduce with temperature. The slope of the isotropic normal consolidation line (INCL) and critical state line (CSL) in the v-p� plane have been observed to be independent of temperature, but both the INCL and the CSL shift downwards to lower locations as temperature increases. The deformations during drained cooling and re heating cycles have been found to be elastic and to simply reflect the expansivity of the soils solid particles. The thermal volume changes during undrained heating have been observed to be direct results of the thermal expansion of water and clay particles. The internal displacement measuring devices have been found to produce reliable data for the variation of strains at elevated temperature.
8
Ghahremannejad, Behrooz. "Thermo-Mechanical Behaviour of Two Reconstituted Clays." University of Sydney. Civil Engineering, 2003. http://hdl.handle.net/2123/492.
Full textAbstract:
The effect of temperature on soil behaviour has been the subject of many studies in recent years due to an increasing number of projects related to the application of high temperature to soil. One example is the construction of facilities for the disposal of hot high level nuclear waste canisters (150-200C) several hundred meters underground in the clay formations. Despite this, the effects and mechanism by which temperature affects the soil properties and behaviour are not fully known. A limited amount of reliable experimental data, technological difficulties and experimental methods employed by different researchers could have contributed to the uncertainties surrounding the soil behaviour at elevated temperature. Also several thermo-mechanical models have been developed for soil behaviour, but their validity needs to be examined by reliable experimental data. In this research, efforts have been made to improve the experimental techniques. Direct displacement measuring devices have been successfully used for the first time to measure axial and lateral displacements of clay samples during tests at various temperatures. The thermo mechanical behaviour of two reconstituted clays has been investigated by performing triaxial and permeability tests at elevated temperature. Undrained and drained triaxial tests were carried out on normally consolidated and over consolidated samples of M44 clay and Kaolin C1C under different effective stresses, and at temperatures between 22C and 100C. Permeability tests were carried out on samples of M44 clay at temperatures between 22C and 50C. The effects of temperature on permeability, volume change, pore pressure development, shear strength and stiffness, stress strain response and critical state parameters for different consolidation histories have been investigated by comparing the results at various temperatures. The results are also compared with the predictions of two models. It has been found that at elevated temperature the shear strength, friction angle and initial small strain stiffness reduce whereas permeability increases. The slope of the swelling line in the v-p� plane has been found to reduce with temperature. The slope of the isotropic normal consolidation line (INCL) and critical state line (CSL) in the v-p� plane have been observed to be independent of temperature, but both the INCL and the CSL shift downwards to lower locations as temperature increases. The deformations during drained cooling and re heating cycles have been found to be elastic and to simply reflect the expansivity of the soils solid particles. The thermal volume changes during undrained heating have been observed to be direct results of the thermal expansion of water and clay particles. The internal displacement measuring devices have been found to produce reliable data for the variation of strains at elevated temperature.
9
Agofack, Nicolaine. "Comportement des ciments pétroliers au jeune âge et intégrité des puits." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1040.
Full textAbstract:
Lors du forage des puits d'hydrocarbure, une pâte de ciment est coulée dans l'espace annulaire entre le cuvelage en acier et les formations géologiques traversées. Pompée à l'état liquide, cette pâte de ciment fait sa prise le long du puits sous différentes conditions de température et de pression. La gaine de ciment ainsi mise en place a pour principales fonctions de promouvoir l'étanchéité pour protéger le casing contre la corrosion, de fournir le support mécanique pour assurer la stabilité du puits et d'isoler les différents fluides dans les couches traversées. Au cours de sa vie dans le puits, depuis le forage à la complétion et de la production à l'abandon, la gaine de ciment est soumise à différentes sollicitations mécaniques et thermiques qui peuvent l'endommager et altérer ses principales fonctions. La réponse de la pâte de ciment soumis à ces sollicitations dépend non seulement des conditions d'hydratation mais aussi de l'histoire des chargements précédemment appliqués. La prédiction du comportement de la gaine de ciment doit donc se faire à l'aide d'une modélisation numérique qui nécessite une loi de comportement pour la pâte de ciment. Le but de cette thèse est d'établir une loi de comportement de la pâte de ciment en cours d'hydratation pendant le jeune-âge (les 144 premières heures). Pour ce faire, des essais calorimétriques, de mesures de vitesse des ondes et des essais œdométriques ont été réalisés sur une pâte de ciment pétrolier classe G (w/c = 0,44) en cours de prise. Les conditions d'hydratation explorées vont de 7 à 30°C pour les températures et de 0,3 à 45MPa pour les pressions. Les résultats expérimentaux ont montré que les déformations volumiques de la pâte de ciment dues à son hydratation (retrait macroscopique) sont considérablement influencées par la contrainte sous laquelle la pâte de ciment s'hydrate. Plus la contrainte d'hydratation est élevée, plus élevé est le retrait macroscopique à 144 heures. Inversement, les déformations irréversibles dues à un cycle de chargement mécanique à cet âge sont moins importantes pour les contraintes plus élevées. Les résultats ont également montrés qu'au cours de la prise du ciment, il existe un temps critique à partir duquel l'application des cycles de chargement mécanique crée des déformations résiduelles dans la pâte de ciment. Ce temps critique arrive à un degré d'hydratation relativement constant, compris entre 0,18 et 0,20. Le modèle « Boundary Nucleation and Growth » a été utilisé pour étudier la dépendance de ce temps critique à la pression et à la température. Pour la modélisation du retrait macroscopique et de la réponse contrainte – déformation de la pâte de ciment, un modèle élasto-plastique chemo-poro-mécanique couplé, prenant en compte la désaturation du milieu, a été développé. Ce modèle utilise une surface de charge fermée de type Cam-Clay et une loi plastique associée. La loi d'écrouissage dépend des déformations volumiques plastiques et du degré d'hydratation. Les paramètres du modèle ont été évalués pour simuler le retrait macroscopique de la pâte de ciment hydratée sous différentes contraintes et températures. A un degré d'hydratation donnée, le modèle permet également de simuler la réponse contrainte-déformation due à un chargement mécaniqueWhen drilling oil & gas well, cement slurry is pumped between the casing and the rock formation. This cement slurry sets at different conditions of temperature and pressure. The role of this cement sheath is to provide zonal isolation of different fluid along the well, to protect the casing against corrosion and to provide mechanical support. During the life of the well, from drilling to completion, production and P&A (plug and abandonment), the cement sheath is submitted to various mechanical and thermal loading that can potentially damage its properties and alter its performance. The behavior of cement paste submitted to theses solicitations depends both on the hydration condition and the loadings previously applied on the cement paste. The prediction of cement sheath behavior should be done by numerical modeling, which needs a constitutive law for cement paste. The purpose of the present work is to establish a constitutive law of cement paste during its hydration at early age (first 144 hours). The approach is based on combined calorimetric, wave velocities and oedometric tests on an oil-well class G cement paste with water-to-cement ratio equals 0.44. The hydration conditions explored are 7 to 30°C for temperature and 0.3 to 45MPa for pressure. The experimental results showed that the volumetric strain due to cement hydration (macroscopic shrinkage) depends considerably on the hydration pressure. At 144 hours of hydration, the macroscopic shrinkage increases with the hydration pressure increase. But, the residual strain due to application of mechanical cycle at this age is less for cement hydrated under higher pressure. The experimental results revealed that during the hydration there is a critical time after which, the application of mechanical loading can potentially induce residual strain in cement paste. This time is reached at constant hydration degree between 0.18 and 0.20. The Boundary Nucleation and Growth model was used to model the pressure and temperature dependence of this critical time. A coupled elasto-plastic chemo-poro-mechanical model is developed to simulate the macroscopic shrinkage of cement paste hydrated at different conditions of temperature and pressure. A modified Cam-Clay type yield surface with associate flow rule is used. The hardening law depends both on the degree of hydration and on the plastic volumetric strain. At constant degree of hydration, the developed model permits to simulate the stress – strain behavior of cement paste due to the mechanical loading
10
NAKANO, MASAKI, AKIRA ASAOKA, and TOSHIHIRO NODA. "SOIL-WATER COUPLED FINITE DEFORMATION ANALYSIS BASED ON A RATE-TYPE EQUATION OF MOTION INCORPORATING THE SYS CAM-CLAY MODEL." 地盤工学会, 2008. http://hdl.handle.net/2237/20062.
Full textBooks on the topic "Cam Clay"
1
Er tong cai ni shou gong. Changchun: Jilin mei shu chu ban she, 1999.
Find full text
2
ning, Zhang, and Wang wen xiao. Bao cai. Shang hai: Shang hai ke xue pu yi chu ban she, 1996.
Find full text
3
Cai su: Su xing fu cai. Shanghai: Shanghai ke ji jiao yu chu ban she, 2006.
Find full text
4
Zeng, Pengzhan Li. Bao zai cai. Xianggang: Bo yi chu ban ji tuan you xian gong si, 2006.
Find full text
5
Endreny, Polly A. Mapping a path to sustainable utilization of bay clam resources in Oregon's 21st century estuaries: An investigation into the potential of Oregon's commercial bay clam fishery. Corvallis, OR: College of Oceanic and Atmospheric Sciences, Oregon State University, Marine Resource Management, 2006.
Find full text
6
Trevisan, Giovanna. Le vongole dell'Alto Adriatico tra ambiente e mercato. Milano, Italy: FrancoAngeli, 2011.
Find full text
7
Guide to Manila clam culture in Washington. [Seattle]: Washington Sea Grant Program, University of Washington, 1992.
Find full text
8
He, Jia. Er tong cai ni shou gong da quan. Changchun: Ji lin mei shu, 2008.
Find full text
9
Bao zai cai. Taibei Shi: Tai shi wen hua gong si, 2000.
Find full text
10
Zhuanze, Xie, ed. Bao zai cai. Taibei Xian Xindian Shi: Sheng huo pin wei wen hua chuan bo you xian gong si, 2002.
Find full textBook chapters on the topic "Cam Clay"
1
Hjiaj, Mohammed, and Géry de Saxcé. "Variational Formulation of the Cam-Clay Model." In IUTAM BookSeries, 165–74. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-9090-5_15.
Full text
2
Anandarajah, A. "The Modified Cam-Clay Model and Its Integration." In Computational Methods in Elasticity and Plasticity, 423–512. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6379-6_12.
Full text
3
Li, Hang Zhou, Hong Jian Liao, Kyoji Sassa, and Gong Hui Wang. "Unified Three-Dimensional Revision of Modified Cam Clay Model." In Engineering Plasticity and Its Applications, 1267–72. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-433-2.1267.
Full text
4
Sun, Yifei, and Yufeng Gao. "A Cam-Clay-Based Fractional Plasticity Model for Granular Soil." In Springer Series in Geomechanics and Geoengineering, 74–78. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-97112-4_17.
Full text
5
Hou, Wei, and Yangping Yao. "Comparison between Feature of Modified Cam-Clay Model and UH Model." In Springer Series in Geomechanics and Geoengineering, 559–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-32814-5_76.
Full text
6
Liu, Kai, and Shengli L. Chen. "Theoretical Analysis on Drained Cylindrical Cavity Expansion in Anisotropic Modified Cam Clay." In Proceedings of GeoShanghai 2018 International Conference: Fundamentals of Soil Behaviours, 281–89. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0125-4_31.
Full text
7
Silvestri, Vincenzo, and Claudette Tabib. "Analysis of Cylindrical Cavity Expansion in Modified Cam Clay with $$ Ko $$Ko Consolidation." In Soil Testing, Soil Stability and Ground Improvement, 297–310. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-61902-6_23.
Full text
8
Silvestri, Vincenzo, and Claudette Tabib. "An Enhanced Solution for the Expansion of Cylindrical Cavities in Modified Cam Clay." In Advances in Numerical Methods in Geotechnical Engineering, 101–17. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-01926-6_7.
Full text
9
Schwager, M. V., A. D. Tzenkov, and G. M. A. Schreppers. "Analysis of Pre-failure and Failure of a Levee on Soft Soil with Modified Cam-Clay Model in DIANA." In Lecture Notes in Civil Engineering, 711–45. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-51085-5_40.
Full text
10
Morton-Jones, David H., and John W. Ellis. "GRP-Clad Lorry Cab." In Polymer Products, 173–83. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4101-4_16.
Full textConference papers on the topic "Cam Clay"
1
Carter, John P., and Martin D. Liu. "Review of the Structured Cam Clay Model." In Geo-Frontiers Congress 2005. Reston, VA: American Society of Civil Engineers, 2005. http://dx.doi.org/10.1061/40771(169)5.
Full text
2
Sadrinezhad, Arezoo, and Kallol Sett. "Probabilistic Elastic–Plastic Cam Clay Response of Soils." In The 2nd World Congress on Civil, Structural, and Environmental Engineering. Avestia Publishing, 2017. http://dx.doi.org/10.11159/icgre17.183.
Full text
3
Nepelski, Krzysztof, and Ewa Błazik-Borowa. "The methodology of choice Cam-Clay model parameters for loess subsoil." In COMPUTER METHODS IN MECHANICS (CMM2017): Proceedings of the 22nd International Conference on Computer Methods in Mechanics. Author(s), 2018. http://dx.doi.org/10.1063/1.5019035.
Full text
4
Bounds, Tommy D., Kanthasamy K. Muraleetharan, and Gerald A. Miller. "Predicting Embankment Behavior Using the Bounding Surface and Modified Cam Clay Models." In Geo-Congress 2022. Reston, VA: American Society of Civil Engineers, 2022. http://dx.doi.org/10.1061/9780784484067.015.
Full text
5
Cui, Ying, and Miao Lin-chang. "Analysis of stability of unsaturated soil slope based on modified cam-clay model." In 2011 International Conference on Electric Technology and Civil Engineering (ICETCE). IEEE, 2011. http://dx.doi.org/10.1109/icetce.2011.5774788.
Full text
6
Wen, Yong, Guanghua Yang, Zhihui Zhong, Xudong Fu, and Yucheng Zhang. "A Similar Cam-clay Model for Sand Based on the Generalized Potential Theory." In Second International Conference on Geotechnical and Earthquake Engineering. Reston, VA: American Society of Civil Engineers, 2013. http://dx.doi.org/10.1061/9780784413128.020.
Full text
7
Mirkalaei, Seyed Mousa Mousavi, David Tran, Vijay Shrivastava, Long Nghiem, Prasanna Chidambaram, Siti Syareena M. Ali, Abdul Hakim Mazeli, and Tan Chee Phuat. "New Approach for Stress Computation during Loading and Unloading in Modified Cam Clay Model." In International Geomechanics Symposium. ARMA, 2022. http://dx.doi.org/10.56952/igs-2022-177.
Full textAbstract:
Abstract Modified Cam-Clay model is often used for simulation of soft geomaterials such as soil or sand. In this model, Young’s modulus continuously changes via the bulk modulus. Poisson’s ratio can change or be kept constant. If the Poisson’s ratio is kept constant, shear modulus will change with time. If the shear modulus is kept constant, Poisson’s ratio is allowed to change with time. In general, the effective stress tensor at time t+1 can be computed when all state variables at time t are known. The material can be either in elastic or plastic mode depending on the stress state. In the case of plasticity, there are many steps involved to obtain a correct stress so that the equilibrium force balance could be satisfied within a tolerance. In the case of plastic deformation when the stress is out of a yield surface at time t+1, the stress must be brought back to the yield surface. The stress computation procedure during loading and unloading has an important effect on the results of deformation and rebounding after a plastic deformation. In this study a new approach for stress computation during loading and plastic unloading path is introduced. In the new proposed method, the relationship between mean effective stress change and volumetric strain change is used as a parameter to determine the amount of plastic deformation during unloading. The new approach will be appropriate for any case with large residual strain and a proposed exponential parameter (n) will determine based on the value of residual strain. A sensitivity analysis was carried out for different values of the exponential parameter which showed the displacement to be gradually less sensitive when the value of the parameter “n” is 1.003 or higher during the unloading stage. This method was then implemented and successfully tested for a study on matured offshore Malaysian field.
8
An, Deng, and Xiao Yang. "Modeling Stress-Strain Behavior of Sand-EPS Beads Lightweight Fills Based on Cam-Clay Models." In GeoHunan International Conference 2009. Reston, VA: American Society of Civil Engineers, 2009. http://dx.doi.org/10.1061/41044(351)9.
Full text
9
Fagundes, Diego F., Khader I. Rammah, Marcio S. S. Almeida, Julio Pequeno, Jose Renato M. S. Oliveira, and Ricardo Garske Borges. "Strength Behaviour Analysis of an Offshore Brazilian Marine Clay." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83008.
Full textAbstract:
The main purpose of this paper is to describe the geotechnical behaviour of a deep water marine clay obtained from Campos basin oil field located offshore the state of Rio de Janeiro in Brazil. The soil samples were obtained at a depth of about 1500 m using a Kullenberg piston corer. Characterization tests were undertaken on the clay samples, including water content, Atterberg limits, particle size distribution and specific density. Isotropic and anisotropic undrained triaxial tests were also carried out on both normal and over-consolidated samples to assess both the conventional strength and Cam-clay parameters. Additionally, oedometer tests were performed to evaluate the compressibility of both undisturbed and reconstituted soil samples. Finally, a series of T-bar penetrometer tests were performed on the mini-drum geotechnical centrifuge at COPPE, the University of Rio de Janeiro to establish the undrained shear strength profile. The results obtained from the T-bar tests were compared with the theoretical strength curves that were established based on the Cam-clay parameters derived from the laboratory tests. The results obtained in this study indicated a useful methodology to assess and capture the behaviour of marine clay. The assessment of strength behaviour of marine clay is quite essential in modelling of wide range of soil-offshore structure interaction problems such as pipelines, mudmats and anchors.
10
Sivasithamparam, Nallathamby, and Jorge Castro. "A Framework for Versatile Shape of Yield Surfaces for Structured Aniso-tropic Soft Soils." In The 13th Baltic Sea Region Geotechnical Conference. Vilnius Gediminas Technical University, 2016. http://dx.doi.org/10.3846/13bsgc.2016.022.
Full textAbstract:
A framework based on logarithmic contractancy is proposed to produce versatile shapes of yield surfaces for structured anisotropic clays. The recently proposed constitutive model (E-SCLAY1S) is an extension of existing model called S-CLAY1S, which is a Cam Clay type model that accounts for anisotropy and structure. A new parameter called contractancy parameter is introduced to control the shape of the yield surface as well as the plastic potential (as an associated flow rule is applied). This new parameter can be used to fit the coefficient of earth pressure at rest, the undrained shear strength or the stiffness under shearing stress paths predicted by the model. The model predicts the uniqueness of the critical state line and its slope is independent of the contractancy parameter. The effect of the shape of the yield surface was investigated on computed results of a benchmark embankment constructed on Bothkennar (Scotland) clay by employing the E-SCLAY1S model as a user-defined soil model into the PLAXIS finite element code. The results demonstrate that the contribution of the shape of yield surface (logarithmic contractancy parameter) have a relatively large effect on lateral movement of subsoil beneath the toe of the embankment compared to the settlement of subsoil at the centre of the embankment.
Reports on the topic "Cam Clay"
1
Gerstl, Zev, Thomas L. Potter, David Bosch, Timothy Strickland, Clint Truman, Theodore Webster, Shmuel Assouline, Baruch Rubin, Shlomo Nir, and Yael Mishael. Novel Herbicide Formulations for Conservation-Tillage. United States Department of Agriculture, June 2009. http://dx.doi.org/10.32747/2009.7591736.bard.
Full textAbstract:
The overall objective of this study was to develop, optimize and evaluate novel formulations, which reduce herbicide leaching and enhance agronomic efficacy. Numerous studies have demonstrated that CsT promotes environmental quality and enhances sustainable crop production, yet continued use of CsT-practices appears threatened unless cost effective alternative weed control practices can be found. The problem is pressing in the southern portion of the Atlantic Coastal Plain region of the eastern USA where cotton and peanut are produced extensively. This research addressed needs of the region’s farmers for more effective weed control practices for CsT systems. HUJI: CRFs for sulfentrazone and metolachlor were developed and tested based on their solubilizion in cationic micelles and adsorption of the mixed micelles on montmorillonite. A better understanding of solubilizing anionic and nonionic organic molecules in cationic micelles was reached. Both CRFs demonstrated controlled release compared to the commercial formulations. A bioassay in soil columns determined that the new sulfentrazone and metolachlor CRFs significantly improve weed control and reduced leaching (for the latter) in comparison with the commercial formulations. ARO: Two types of CRFs were developed: polymer-clay beads and powdered formulations. Sand filter experiments were conducted to determine the release of the herbicide from the CRFs. The concentration of metolachlor in the initial fractions of the effluent from the commercial formulation reached rather high values, whereas from the alginate-clay formulations and some of the powdered formulations, metolachlor concentrations were low and fairly constant. The movement of metolachlor through a sandy soil from commercial and alginate-clay formulations showed that the CRFs developed significantly reduced the leaching of metolachlor in comparison to the commercial formulation. Mini-flume and simulated rainfall studies indicated that all the CRFs tested increased runoff losses and decreased the amount of metolachlor found in the leachate. ARS: Field and laboratory investigations were conducted on the environmental fate and weed control efficacy of a commercially available, and two CRFs (organo-clay and alginate-encapsulated) of the soil-residual herbicide metolachlor. The environmental fate characteristics and weed control efficacy of these products were compared in rainfall simulations, soil dissipations, greenhouse efficacy trials, and a leaching study. Comparisons were made on the basis of tillage, CsT, and conventional, i.e no surface crop residue at planting (CT). Strip-tillage (ST), a commonly used form of CsT, was practiced. The organo-clay and commercial metolachlor formulations behaved similarly in terms of wash off, runoff, soil dissipation and weed control efficacy. No advantage of the organo-clay over the commercial metolachlor was observed. Alginate encapsulated metolachlor was more promising. The dissipation rate for metolachlor when applied in the alginate formulation was 10 times slower than when the commercial product was used inferring that its use may enhance weed management in cotton and peanut fields in the region. In addition, comparison of alginate and commercial formulations showed that ST can effectively reduce the runoff threat that is commonly associated with granular herbicide application. Studies also showed that use of the alginate CRF has the potential to reduce metolachlor leaching. Overall study findings have indicated that use of granular herbicide formulations may have substantial benefit for ST-system weed management for cotton and peanut production under Atlantic Coastal Plain conditions in the southeastern USA. Commercial development and evaluation at the farm scale appears warranted. Products will likely enhance and maintain CsT use in this and other regions by improving weed control options.
2
Bradford, Joe, Itzhak Shainberg, and Lloyd Norton. Effect of Soil Properties and Water Quality on Concentrated Flow Erosion (Rills, Ephermal Gullies and Pipes). United States Department of Agriculture, November 1996. http://dx.doi.org/10.32747/1996.7613040.bard.
Full textAbstract:
Concentrated flow erosion in rills, pipes, ephermal gullies, and gullies is a major contributor of downstream sedimentation. When rill or gullies form in a landscape, a 3- to 5-fold increase in soil loss commonly occurs. The balance between the erosive power of the flow and the erosion resistance of the bed material determines the rate of concentrated flow erosion. The resistance of the bed material to detachment depends primarily on the magnitude of the interparticle forces or cohesion holding the particles and aggregates together. The effect of soil properties on bed material resistance and concentrated flow erosion was evaluated both in the laboratory and field. Both rill erodibility and critical hydraulic shear were greater when measured in 9.0 m long rills under field conditions compared with laboratory mini-flumes. A greater hydraulic shear was required to initiate erosion in the field compared to the mini-flume because of the greater aggregate and clod size and stability. Once erosion was initiated, however, the rate of erosion as a function of hydraulic shear was greater under field conditions because of the greater potential for slaking upon wetting and the greater soil surface area exposed to hydraulic shear. Erosion tests under controlled laboratory conditions with the mini-flume allowed individual soil variables to be studied. Attempts to relate rill erosion to a group soil properties had limited success. When individual soil properties were isolated and studied separately or grouped separately, some trends were identified. For example, the effect of organic carbon on rill erodibility was high in kaolinitic soils, low in smectitic soils, and intermediate in the soils dominated by illite. Slow prewetting and aging increased the cohesion forces between soil particles and decreased rill erodibility. Quick prewetting increased aggregate slaking and increased erodibility. The magnitude of the effect of aging depended upon soil type. The effect of clay mineralogy was evaluated on sand/clay mixtures with montmorillonite (M), Illite (I), and kaolinite (K) clays. Montmorillonite/sand mixtures were much less erodible than either illite or kaolonite sand mixtures. Na-I and Na-K sand mixtures were more erodible than Ca-I and Ca-K due to increased strength from ionic bonding and suppression of repulsive charges by Ca. Na-M was less erodiblethan Ca-M due to increased surface resulting from the accessibility of internal surfaces due to Na saturation. Erodibility decreased when salt concentration was high enough to cause flocculation. This occurred between 0.001 mole L-1 and 0.01 mole L-1. Measuring rill erodibility in mini-flumes enables the measurement of cohesive forces between particles and enhances our ability to learn more about cohesive forces resisting soil detachment under concentrated water flow.
3
Smith, Kiara. Anaerobic Degradation of Polycyclic Aromatic Hydrocarbons at a Creosote-Contaminated Superfund Site and the Significance of Increased Methane Production in an Organophilic Clay Sediment Cap. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.101.
Full text
4
Thornell, Travis, Charles Weiss, Sarah Williams, Jennifer Jefcoat, Zackery McClelland, Todd Rushing, and Robert Moser. Magnetorheological composite materials (MRCMs) for instant and adaptable structural control. Engineer Research and Development Center (U.S.), November 2020. http://dx.doi.org/10.21079/11681/38721.
Full textAbstract:
Magnetic responsive materials can be used in a variety of applications. For structural applications, the ability to create tunable moduli from relatively soft materials with applied electromagnetic stimuli can be advantageous for light-weight protection. This study investigated magnetorheological composite materials involving carbonyl iron particles (CIP) embedded into two different systems. The first material system was a model cementitious system of CIP and kaolinite clay dispersed in mineral oil. The magnetorheological behaviors were investigated by using parallel plates with an attached magnetic accessory to evaluate deformations up to 1 T. The yield stress of these slurries was measured by using rotational and oscillatory experiments and was found to be controllable based on CIP loading and magnetic field strength with yield stresses ranging from 10 to 104 Pa. The second material system utilized a polystyrene-butadiene rubber solvent-cast films with CIP embedded. The flexible matrix can stiffen and become rigid when an external field is applied. For CIP loadings of 8% and 17% vol %, the storage modulus response for each loading stiffened by 22% and 74%, respectively.
5
Ahmed, Nabil, Anna Marriott, Nafkote Dabi, Megan Lowthers, Max Lawson, and Leah Mugehera. Inequality Kills: The unparalleled action needed to combat unprecedented inequality in the wake of COVID-19. Oxfam, January 2022. http://dx.doi.org/10.21201/2022.8465.
Full textAbstract:
The wealth of the world’s 10 richest men has doubled since the pandemic began. The incomes of 99% of humanity are worse off because of COVID-19. Widening economic, gender, and racial inequalities—as well as the inequality that exists between countries—are tearing our world apart. This is not by chance, but choice: “economic violence” is perpetrated when structural policy choices are made for the richest and most powerful people. This causes direct harm to us all, and to the poorest people, women and girls, and racialized groups most. Inequality contributes to the death of at least one person every four seconds. But we can radically redesign our economies to be centered on equality. We can claw back extreme wealth through progressive taxation; invest in powerful, proven inequality-busting public measures; and boldly shift power in the economy and society. If we are courageous, and listen to the movements demanding change, we can create an economy in which nobody lives in poverty, nor with unimaginable billionaire wealth—in which inequality no longer kills.
6
Litaor, Iggy, James Ippolito, Iris Zohar, and Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600037.bard.
Full textAbstract:
Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.
7
El Badawy, Amro, and Ashraf Rahim. Evaluation of Nanoclay Additives for Improving Resistance to Moisture Damage in Hot Mix Asphalt (HMA). Mineta Transportation Institute, January 2023. http://dx.doi.org/10.31979/mti.2023.2151.
Full textAbstract:
Transportation has an enormous impact on the U.S. economy and on the lives of all Americans. Many modes of transportation rely on pavement, but pavement conditions deteriorate over time because of the combined effects of traffic and climate. Exposure to moisture often causes premature failure of asphalt pavements as it reduces the stiffness of the asphalt and enables stripping of the asphalt from the aggregate. This research evaluates the effectiveness of clay nanomaterials (i.e., nanoclays) in improving the resistance of hot mix asphalt (HMA) to moisture damage and compares the enhancement results to anti-stripping additives commonly used in pavement construction. Two types of surface-modified nanoclay, lime-treated aggregate, and two amine-based liquid antistripping agents (HP Plus and LOF 6500) were evaluated for improving HMA’s moisture resistance. All additives tested for reducing moisture damage resulted in dry and wet tensile strength of the modified mixes higher than the minimum specified by Caltrans 2018 Standard Specifications (100 psi for dry tensile strength and 70 psi for wet tensile strength). The Tensile Strength Ratio (TSR) of all HMA modified mixes was higher than 0.80, which is the minimum specified by the Superpave mix design method (Asphalt Mix Design Methods MS-2, Asphalt Institute) and exceeded the TSR of the control mix. The TSR for HMA mixes modified using nanoclays were comparable to those for HMA mixes modified using liquid antistripping and lime slurry treated aggregate. Liquid antistripping agents tested herein were the least costly additive at an approximately $2.0/ton added cost. This research can be used to better understand pavement deterioration to enable the most efficient and cost-effective construction and preservation of our nation's critical transportation infrastructure.
8
Akinleye, Taiwo, Idil Deniz Akin, Amanda Hohner, Indranil Chowdhury, Richards Watts, Xianming Shi, Brendan Dutmer, James Mueller, and Will Moody. Evaluation of Electrochemical Treatment for Removal of Arsenic and Manganese from Field Soil. Illinois Center for Transportation, June 2021. http://dx.doi.org/10.36501/0197-9191/21-019.
Full textAbstract:
Soils containing inorganic compounds are frequently encountered by transportation agencies during construction within the right-of-way, and they pose a threat to human health and the environment. As a result, construction activities may experience project delays and increased costs associated with management of inorganic compounds containing soils required to meet environmental regulations. Recalcitrance of metal-contaminated soils toward conventional treatment technologies is exacerbated in clay or organic content-rich fine-grained soils with low permeability and high sorption capacity because of increased treatment complexity, cost, and duration. The objective of this study was to develop an accelerated in situ electrochemical treatment approach to extract inorganic compounds from fine-grained soils, with the treatment time comparable to excavation and off-site disposal. Three reactor experiments were conducted on samples collected from two borehole locations from a field site in Illinois that contained arsenic (As)(~7.4 mg/kg) and manganese (Mn)(~700 mg/kg). A combination of hydrogen peroxide (H2O2) and/or citrate buffer solution was used to treat the soils. A low-intensity electrical field was applied to soil samples using a bench-scale reactor that resembles field-scale in situ electrochemical systems. For the treatment using 10% H2O2 and citrate buffer solution, average removal of 23% and 8% were achieved for Mn and As, respectively. With 4% H2O2 and citrate buffer, 39% and 24% removal were achieved for Mn and As; while using only citrate buffer as the electrolyte, 49% and 9% removal were achieved for Mn and As, respectively. All chemical regimes adopted in this study reduced the inorganic compound concentrations to below the maximum allowable concentration for Illinois as specified by the Illinois Environmental Protection Agency. The results from this work indicate that electrochemical systems that leverage low concentrations of hydrogen peroxide and citrate buffer can be effective for remediating soils containing manganese and arsenic.
9
Russo, David, and William A. Jury. Characterization of Preferential Flow in Spatially Variable Unsaturated Field Soils. United States Department of Agriculture, October 2001. http://dx.doi.org/10.32747/2001.7580681.bard.
Full textAbstract:
Preferential flow appears to be the rule rather than the exception in field soils and should be considered in the quantitative description of solute transport in the unsaturated zone of heterogeneous formations on the field scale. This study focused on both experimental monitoring and computer simulations to identify important features of preferential flow in the natural environment. The specific objectives of this research were: (1) To conduct dye tracing and multiple tracer experiments on undisturbed field plots to reveal information about the flow velocity, spatial prevalence, and time evolution of a preferential flow event; (2) To conduct numerical experiments to determine (i) whether preferential flow observations are consistent with the Richards flow equation; and (ii) whether volume averaging over a domain experiencing preferential flow is possible; (3) To develop a stochastic or a transfer function model that incorporates preferential flow. Regarding our field work, we succeeded to develop a new method for detecting flow patterns faithfully representing the movement of water flow paths in structured and non-structured soils. The method which is based on application of ammonium carbonate was tested in a laboratory study. Its use to detect preferential flow was also illustrated in a field experiment. It was shown that ammonium carbonate is a more conservative tracer of the water front than the popular Brilliant Blue. In our detailed field experiments we also succeeded to document the occurrence of preferential flow during soil water redistribution following the cessation of precipitation in several structureless field soils. Symptoms of the unstable flow observed included vertical fingers 20 - 60 cm wide, isolated patches, and highly concentrated areas of the tracers in the transmission zone. Soil moisture and tracer measurements revealed that the redistribution flow became fingered following a reversal of matric potential gradient within the wetted area. Regarding our simulation work, we succeeded to develop, implement and test a finite- difference, numerical scheme for solving the equations governing flow and transport in three-dimensional, heterogeneous, bimodal, flow domains with highly contrasting soil materials. Results of our simulations demonstrated that under steady-state flow conditions, the embedded clay lenses (with very low conductivity) in bimodal formations may induce preferential flow, and, consequently, may enhance considerably both the solute spreading and the skewing of the solute breakthrough curves. On the other hand, under transient flow conditions associated with substantial redistribution periods with diminishing water saturation, the effect of the embedded clay lenses on the flow and the transport might diminish substantially. Regarding our stochastic modeling effort, we succeeded to develop a theoretical framework for flow and transport in bimodal, heterogeneous, unsaturated formations, based on a stochastic continuum presentation of the flow and a general Lagrangian description of the transport. Results of our analysis show that, generally, a bimodal distribution of the formation properties, characterized by a relatively complex spatial correlation structure, contributes to the variability in water velocity and, consequently, may considerably enhance solute spreading. This applies especially in formations in which: (i) the correlation length scales and the variances of the soil properties associated with the embedded soil are much larger than those of the background soil; (ii) the contrast between mean properties of the two subdomains is large; (iii) mean water saturation is relatively small; and (iv) the volume fraction of the flow domain occupied by the embedded soil is relatively large.
10
Pelletier, Austin, Amanda Hohner, Idil Deniz Akin, Indranil Chowdhury, Richard Watts, Xianming Shi, Brendan Dutmer, and James Mueller. Bench-scale Electrochemical Treatment of Co-contaminated Clayey Soil. Illinois Center for Transportation, June 2021. http://dx.doi.org/10.36501/0197-9191/21-018.
Full textAbstract:
Industrial soil contamination is frequently unearthed by transportation agencies during construction within the right-of-way. As a result, transportation agencies may experience construction delays. Soils co-contaminated with high-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) and metals are commonly encountered in Illinois and exhibit recalcitrance towards conventional treatment technologies. This issue is exacerbated in the fine-grained soils common to Illinois, where low-permeability and immense sorption capacity increase treatment complexity, cost, and duration. Contaminated sites are spatially and temporally restrictive and require rapid in situ treatments, whereas conventional soil remediation requires 1 to 3 years on average. Consequently, transportation agencies typically pursue excavation and off-site disposal for expediency. However, this solution is expensive, so a comparatively expeditious and affordable treatment alternative is needed to combat the increasing cost of hazardous waste disposal. The objective of this work was to develop an accelerated in situ treatment approach adaptable for use at any construction site to cost-effectively remove HMW-PAHs and metals from clayey soil. It was hypothesized that an in situ electrochemical treatment which augments electrokinetics with H2O2 could remediate both HMW-PAHs and metals in less than a month. Bench-scale reactors resemblant of field-scale in situ electrokinetic systems were designed and fabricated to assess the electrochemical treatment of clayey soils contaminated with HMW-PAHs and metals. Pyrene, chromium, and manganese were used as model contaminants, spiked into kaolinite as a model clay. Electrokinetics were imposed by a low-intensity electrical field distributed by graphite rods. Electrolytic H2O2 systems were leveraged to distribute electrical current and facilitate contaminant removal. Average contaminant removals of 100%, 42.3%, and 4.5% were achieved for pyrene, manganese, and chromium, respectively. Successful development of this bench-scale treatment approach will serve to guide transportation agencies in field-scale implementation. The results from this work signify that electrochemical systems that leverage eco-friendly oxidant addition can replace excavation and disposal as a means of addressing clayey soils co-contaminated with HMW-PAHs and metals.