A utilização de solo natural misturado com bentonita empregado em camadas impermeáveis para retenção de contaminante é bastante comum em aterros sanitários. Neste trabalho, serão apresentados os resultados de ensaios com misturas de solo-bentonita nos teores de 3%, 5% e 7%, utilizando-se um solo arenoso proveniente da região de Pindorama (SP). Os ensaios de condutividade hidráulica para o solo-bentonita foram realizados em permeâmetros de parede flexível. Os resultados obtidos indicam que para os teores de 5% e 7% de bentonita a condutividade hidráulica apresenta-se com valores adequados para a construção de barreiras impermeáveis. A resistência ao cisalhamento do solo compactado puro e das misturas compactadas foi avaliada através de ensaios triaxiais do tipo consolidado não drenado (CU) e ensaios de compressão simples. A coesão efetiva e o ângulo de atrito efetivo do solo aumentou e diminuiu, respectivamente, com a adição de bentonita. Os ensaios de resistência à compressão simples para as misturas com 5% de bentonita atingiram valores aceitáveis para o emprego em camadas impermeabilizantes. / It is becoming very common the use of soil-bentonite mixtures for building sanitary landfill liners with the purpose of retaining pollutants. This work shows the results of hydraulic conductivity and shear strength tests performed with soil-bentonite mixtures with 3%, 5% and 7% bentonite content. The natural soil was gathered in the Pindorama area, which is located in the northeast of Sao Paulo state. The hydraulic conductivity tests were performed in a flexible wall permeameter. Test results show that mixtures with 5% and 7% bentonite content are suitable, in terms of hydraulic conductivity, for construction of sanitary landfill liners. The shear strength parameters of natural soil and mixtures have been assessed performing undrained triaxial compression tests and unconfined compression tests. The effective cohesion and the effective friction angle increased and decreased with the increase of the bentonite content, respectively. The unconfined compression test results have shown that mixtures with 5% bentonite content are suitable, in terms of shear strength, for construction of sanitary landfill liners.

Orientador: Alexandre Campane Vidal / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-24T10:58:04Z (GMT). No. of bitstreams: 1 Costanzo_CaetanoPontes_M.pdf: 3384236 bytes, checksum: 7b4516eef162c87ff3e03f0d56f08215 (MD5) Previous issue date: 2014 / Resumo: Em face da crescente demanda de execução de projetos de remediação de aquíferos contaminados, a técnica de bombeamento e tratamento está sendo utilizada de forma significativa. Esta ferramenta de recuperação ambiental consiste no bombeamento da água subterrânea em pontos estrategicamente posicionados de maneira a gerar uma barreira hidráulica que impeça o avanço da extensão de uma pluma de contaminação. Em áreas com alta heterogeneidade litológica, a organização espacial dos valores de condutividade hidráulica (K) em subsuperfície apresenta incertezas associadas à variabilidade na distribuição das fácies. No presente estudo foram analisadas estas incertezas por meio de métodos geoestatísticos (krigagem da indicatriz e simulações estocásticas) e também a partir de simulações numéricas de fluxo e transporte de contaminantes. Estas ferramentas permitiram a análise das possibilidades de deslocamentos espaciais das plumas de contaminação, bem como possíveis cenários de bombeamento e tratamento numa área contaminada, em função de distintos campos aleatórios de condutividade locais, devido à complexidade geológica. A partir da krigagem da indicatriz foi possível elaborar um modelo geoestatístico de fácies que foi utilizado como ferramenta para validar o uso da condutividade hidráulica em função de cada litologia, definindo assim os possíveis grupos de hidrofácies presentes na área. Por meio das simulações estocásticas foram gerados vinte campos distintos de condutividade hidráulica, os quais configuraram distintas distribuições espaciais das áreas das plumas de contaminação, como também cenários otimista, intermediário e pessimista para o deslocamento das mesmas. Foram simulados três cenários de bombeamento e tratamento resultando nove situações desta técnica de remediação. Dessa forma, os efeitos da heterogeneidade atrelada à condutividade hidráulica evidenciaram que, para a execução de um projeto de remediação por bombeamento e tratamento em áreas com certa heterogeneidade geológica, é necessária a análise de incertezas atreladas ao diagnostico hidrogeológico. Ao considerar modelos com homogeneidade na condutividade e mais simplistas, o projeto de remediação pode vir a ser ineficiente aumentando o tempo para a recuperação ambiental local e consequentemente aumentando os custos / Abstract: Due to the growing demand for project execution remediation of contaminated aquifers, the pump-and-treat is being used significantly. This remediation technique consists in groundwater pumping in strategically placed at points to generate a hydraulic barrier to prevent the advance of a contamination plume. In areas with high lithological heterogeneity, the spatial organization of the hydraulic conductivity (K) values in the subsurface introduces uncertainties associated with the variability in the distribution of facies. In this study these uncertainties were evaluated using geostatistical methods (indicator kriging and stochastic simulations) and also from numerical simulations of flow and contaminant transport. These tools enable the analysis of the contamination plumes areas, as well as scenarios for pump-and-treat, due to different random fields of local conductivity according to the geological complexity. By indicator kriging, was possible to provide a geostatistical facies model which was used as a tool to validate the hydraulic conductivity as a function of each lithology, thus defining the possible hydrofacies groups in the area. The stochastic simulations generated twenty distinct hydraulic conductivity fields, which represented different spatial distributions of contamination plumes, as well as scenarios optimistic, intermediate and pessimistic to offset these. Three scenarios for pump-and-treat were simulated resulting nine situations of this remediation technique. Therefore the effects of heterogeneity associated with hydraulic conductivity showed that, for the remediation design in areas with certain geological heterogeneity, the analysis of uncertainties linked to hydrogeological studies is needed. When considering models with homogeneous conductivity and most simplistic, the remediation project may prove to be inefficient increasing the time to the project and consequently increasing costs / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

Los modelos numéricos son herramientas fundamentales para realizar predicciones de muchos problemas enfrentados por ingenieros geotécnicos y geoambientales. Sin embargo, para que estos modelos puedan realizar predicciones confiables, los parámetros de entrada del modelo deben ser estimados considerando el efecto escala. En este contexto, esta tesis se concentra en las reglas del cambio de escala de los parámetros de flujo y transporte de masa en un suelo tropical a través de estudios numéricos, de laboratorio y de campo. Esta está organizada en cuatro partes. Primero, la heterogeneidad, correlación y correlación cruzada entre los parámetros de transporte de solutos (dispersividad, ¿, y coeficiente de partición, Kd) y las propiedades del suelo fueron estudiadas en detalle. En esta parte fue verificado que la conductividad hidráulica (K) y los parámetros de transporte de solutos son altamente heterogéneos, mientras que las propiedades del suelo no lo son. La correlación espacial de ¿ y K con variables estadísticamente significativas fue estudiada. Este resultado probablemente podrá mejorar la estimación en casos de estudios de pequeña escala debido a que solo fue observada correlaciones de hasta 2,5 m. Este estudio fue un primer intento de evaluar la variación espacial en el coeficiente de correlación de los parámetros de transporte de un soluto reactivo y de un no reactivo, indicando las variables más relevantes y aquella que debería ser incluida en estudios futuros. En la segunda parte, el efecto escala en K, dispersividad y coeficiente de partición de potasio y clorito fue estudiado experimentalmente a través de experimentos de laboratorio y de campo. El objetivo de esta parte fue contribuir a la discusión sobre el efecto escala en K, ¿ y Kd, y entender como estos parámetros se comportan con el cambio de escala de medición. La dispersividad tiende a aumentar con la altura de la muestra de manera exponencial. El coeficiente de partición tiende a aumentar con la altura, el diámetro y el volumen de la muestra. Estas diferencias encontradas en los parámetros de acuerdo con la escala de medición deben ser considerados cuando estos valores sean usados posteriormente como datos de entrada de modelos numéricos; de otra manera, las respuestas pueden ser malinterpretadas. Tercero, análisis estocásticos tridimensionales de cambio de escala de la conductividad hidráulica fueron realizados usando los métodos de promedios simples y de Laplace con piel para una variedad de tamaños de bloques usando mediciones reales de K. En esta parte son demostrados los errores que pueden ser introducidos al usar métodos determinísticos de cambio de escala usando promedios simples de las mediciones de K sin llevar en consideración la correlación espacial. La aplicación muestra que la heterogeneidad de K puede ser incorporada en la práctica diaria del modelador geotécnico. Los aspectos que considerar durante un proceso de cambio de escala también son discutidos. Finalmente, la dependencia del exponente de la norma-p como función del tamaño del bloque fue analizada. En la última parte, una aplicación de cambio de escala estocástico del coeficiente de dispersión hidrodinámica D y del factor de retardo R fue realizada usando datos reales con el objetivo de reducir la falta de casos de investigación experimental de cambio de escala de parámetros de transporte de solutos reactivos. El cambio de escala de D fue realizado usando el método de macrodispersión. El método de promedio simple de norma-p fue usado para realizar el cambio de escala de R. Una buena propagación de incertidumbres fue alcanzada. Métodos simples de cambio de escala pueden ser introducidos en la práctica del modelaje usando programas comerciales de transporte y conseguir reproducir el transporte en escala gruesa, pero puede requerir correcciones con el objetivo de reducir el efecto de suavizado de la heterogeneidad causado por el / Numerical models are becoming fundamental tools to predict a range of complex problems faced by geotechnical and geo-environmental engineers. However, to render the model reliable for future predictions, the model input parameters must be determined with consideration of the scale effects. In this context, this thesis focuses on upscaling of water flow and mass transport in a tropical soil by means of numerical, laboratory and field studies. This thesis is organized in four parts. First, the heterogeneity, correlation and cross-correlation between solute transport parameters (dispersivity, ¿, and partition coefficient, Kd) and soil properties were studied in detail. In this part, it was verified that the hydraulic conductivity (K) and solute transport parameters are highly heterogeneous, while soil properties not. Spatial correlation of ¿, K, and statistically significant variables were studied, and it would probably improve the estimation only in a small-scale study, since the spatial correlation were only observed up to 2.5 m. This study was a first attempt to evaluate the spatial variation in the correlation coefficient of transport parameters of a reactive and a nonreactive solute, indicating the more relevant variables and the one that should be included in future studies. In the second part, scale effect on K, dispersivity and partition coefficient of potassium and chloride is studied experimentally by means of laboratory and field experiments. The purpose of was to contribute to the discussion about scale effects on K, ¿ and Kd and understanding how these parameters behave with the change in the scale of measurement. Results shows that K increases with scale, regardless of the method of measurement. Dispersivity trends to increases exponentially with the sample height. Partition coefficient, tend to increase with sample length, diameter and volume. These differences in the parameters according to the scale of measurement must be considered when these observations are later used as input to numerical models, otherwise the responses can be misrepresented. Third, stochastic analysis of three-dimensional hydraulic conductivity upscaling was performed using a simple average and the Laplacian-with-skin methods for a variety of block sizes using real K measurements. In this part it was demonstrated the errors that can be introduced by using a deterministic upscaling using simple averages of the measured K without accounting for the spatial correlation. The application shows that K heterogeneity can be incorporated in the daily practice of the geotechnical modeler. The aspects to consider when performing the upscaling were also discussed. Finally, the dependence of the exponent of the p-norm as a function of the block size was analyzed. In the last part, an application of stochastic upscaling of hydrodynamic dispersion coefficient (D) and retardation factor (R) was performed using real data aiming to reduce the lack in experimental upscaling of reactive solute transport research. Upscaling of D was done using macrodispersion method. Simple average method based on p-norm was used to perform R upscaling. A good propagation of the uncertainties was achieved. Simple upscaling methods can be incorporated to the modeling practice using commercial transport codes and properly reproduce de transport at coarse scale but may require corrections to reduce smoothing of the heterogeneity caused by the upscaling procedure. / Els models numèrics s'estan constituint en eines fonamentals per a realitzar prediccions d'una àmplia gamma de problemes enfrontats per enginyers geotècnics i geoambientales. No obstant açò, perquè aquests models puguen realitzar prediccions fiables, els paràmetres d'entrada del model han de considerar l'efecte escala. En aquest context, aquesta tesi es concentra en les regles del canvi d'escala dels paràmetres de flux i transport de massa en un sòl tropical a través d'estudis numèrics, de laboratori i de camp. Aquesta tesi està organitzada en quatre parts. Primer, l'heterogeneïtat, correlació i correlació creuada entre els paràmetres de transport de soluts (dispersivitat, ¿, i coeficient de partició, Kd) i les propietats del sòl van ser estudiades detalladament. En aquesta part va ser verificat que la conductivitat hidràulica (K) i els paràmetres de transport de soluts són altament heterogenis, mentre que les propietats del sòl no ho són. La correlació espacial de ¿ i K amb variables estadísticament significatives va ser estudiada. Aquest resultat probablement podrà millorar l'estimació en casos d'estudis de xicoteta escala a causa que solament va ser observada correlacions de fins a 2,5 m. Aquest estudi va ser un primer intent d'avaluar la variació espacial en el coeficient de correlació dels paràmetres de transport d'un solut reactiu i d'un no reactiu, indicant les variables més rellevants i aquelles que haurien de ser inclosas en estudis futurs. En la segona part, l'efecte escala en K, dispersivitat i coeficient de partició de potassi i clorito va ser estudiat experimentalment a través d'experiments de laboratori i de camp. L'objectiu d'aquesta part va ser contribuir a la discussió sobre l'efecte escala en K, ¿ i Kd, i entendre com aquests paràmetres es comporten amb el canvi d'escala de mesurament. La dispersivitat tendeix a augmentar amb l'altura de la mostra, és a dir, amb la longitud del transport, de manera exponencial. El coeficient de partició tendeix a augmentar amb l'altura, el diàmetre i el volum de la mostra. Aquestes diferències en els paràmetres d'acord amb l'escala de mesurament han de ser considerats quan aquests valors siguen usats posteriorment com a dades d'entrada de models numèrics; d'una altra manera, les respostes poden ser malament interpretades. Tercer, anàlisis estocàstiques tridimensionals de canvi d'escala de la conductivitat hidràulica van ser realitzats usant els mètodes de mitjanes simples i de Laplace amb pell per a una varietat de grandàries de blocs usant mesuraments reals de K. En aquesta part són demostrats els errors que poden ser introduïts en usar mètodes determinístics de canvi d'escala usant mitjanes simples dels mesuraments de K sense tindre en consideració la correlació espacial. L'aplicació mostra que l'heterogeneïtat de K pot ser incorporada en la pràctica diària del modelador geotècnic. Els aspectes a considerar durant un procés de canvi d'escala també són discutits. Finalment, la dependència de l'exponent de la norma-p com a funció de la grandària del bloc va ser analitzada. En l'última part, una aplicació de canvi d'escala estocàstic del coeficient de dispersió hidrodinámica D i del factor de retard R va ser realitzada usant dades reals amb l'objectiu de reduir la falta de casos de recerca experimental de canvi d'escala de paràmetres de transport de soluts reactius. El canvi d'escala de D va ser realitzat usant el mètode de macrodispersió. El mètode de mitjana simple de norma-p va ser usat per a realitzar el canvi d'escala de R. Una bona propagació d'incerteses va ser aconseguida. Mètodes simples de canvi d'escala poden ser introduïts en la pràctica de la modelació usant programes comercials de transport i aconseguir reproduir el transport en escala gruixuda, però pot requerir correccions amb l'objectiu de reduir l'efecte de suavitzat de l'heterogeneïtat causat pel procés de canvi d'escala. / Almeida De Godoy, V. (2018). Upscaling of water flow and mass transport in a tropical soil: numerical, laboratory and field studies [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/102405 / TESIS

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23172号 / 工博第4816号 / 新制||工||1753(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 角 哲也, 准教授 竹門 康弘, 准教授 Sameh Kantoush / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

<div><div>This thesis analyzed three fundamental fluid dynamics problems arising from multiphase flows that may be encountered in hydraulically fractured flow passages. During hydraulic fracturing (``fracking''), complex fluids laden with proppants are pumped into tight rock formations. Flow passages in these formation are naturally heterogeneous with geometric variations, which become even more pronounced due to fracking. Upon increasing the flow area (and, thus, the conductivity of the rock), crude oil, shale gas or other hydrocarbons can then flow out of the formation more easily. In this context, we encounter the following three fluid mechanical phenomena: fluid--fluid interfacial instabilities, flow-wise variation of the hydraulic conductivity, and particle migration in the pumped fluids. </div><div><br></div><div>First, we studied the (in)stability of the interface between two immiscible liquids in angled (tapered) Hele-Shaw cells, as model of a non-uniform flow passage. We derived an expression for the growth rate of perturbations to the flat interface and for the critical capillary number, as functions of the small gap gradient (taper). On this basis, we formulated a three-regime theory to describe the interface's stability. Specifically, we found a new regime in which the growth rate changes from negative to positive (converging cells), or from positive to negative (diverging cells), thus the interface's stability can change type at some location in the cell. We conducted three-dimensional OpenFOAM simulations of the Navier--Stokes equations, using the continuous surface force method, to validate the theory.</div><div><br></div><div>Next, we investigated the flow-wise variation of the hydraulic conductivity inside a non-uniformly shaped fracture with permeable walls. Using lubrication theory for viscous flow, in conjunction with the Beavers--Joseph--Saffman boundary condition at the permeable walls, we obtained an analytical expression for the velocity profile, conductivity, and wall permeation velocity. The new expression highlights the effects of geometric variation, </div><div>the permeability of the walls, </div><div>and the effect of flow inertia.</div><div>The theory was validated against OpenFOAM simulations of the Navier--Stokes equations subject to a tensorial slip boundary condition.</div><div><br></div><div>Finally, we extended the utility of phenomenological models for particle migration in shear flow using the physics-informed neural networks (PINNs) approach. We first verified the approach for solving the inverse problem of radial particle migration in a non-Brownian suspension in an annular Couette flow. Then, we applied this approach to both non-Brownian and Brownian suspensions in Poiseuille slot flow, for which a definitive calibration of the phenomenological migration model has been lacking. Using PINNs, we identified the unknown/empirical parameters in the physical model, showing that (unlike assumptions made in the literature) they depend on the bulk volume fraction and shear P\'eclet number. </div></div>

The main purpose of this diploma thesis is to check up and compare empirical formulae (Hazen, Slichter, Terzaghi, Beyer, Zauerbrej, Krüger, Kozeny, Zunker, Zamarin, USBR, Pavčič) for determining hydraulic conductivity, which are mostly publicated in different and dimensionally inhomogenous forms. The importance of an accurate determination of hydraulic conductivity and the derivation of a general formula for determining hydraulic conductivity are listed in the first part of this diploma thesis. Assessment methodology and empirical formulae in dimensional homogenous form are described in the following part. Evaluating and comparing of empirical formulae is mentioned in the last part. According to the results of this diploma thesis, the best empirical formula for determinig and estimating hydraulic conductivity is Hazen formula. Formula with the widest range of validity is Slichter formula.

The aim of this thesis is to compare the results of water infiltration from field tests, from laboratories and from numerical modeling at two selected locations. The first objective is the search procedure and the description of both sites and its adjacent areas. Further work continues with infiltration field tests using ring infiltrometer, at first theoretically for each method, and then practically with own personal measurements in the field. Further from the collected soil samples the measurements are performed in the laboratory, first in the permeameter, and followed by the grain size distribution test, from which the hydraulic conductivity is derived by using empirical formulas. At last the numerical modeling is used and all the results are compared. In the final phase of thesis the recommendations are given for infiltration at various locations and comparsion of the infiltration methods.

Up-to-date methods of numerical modelling of random fields were applied to investigate some features of solute transport in saturated porous media with stochastic hydraulic conductivity. The paper describes numerical experiments which were performed and presents the first results.

Permeable Interlocking Concrete Pavements (PICP) have seen increased popularity in the principles of Water Sensitive Urban Design and Sustainable Drainage Systems in recent years. To address certain design queries that still existed in industry, a two-year experimental study was conducted. It entailed the construction of an Infiltration Table Apparatus and subjecting a representative volume of PICP to hydraulic testing within it. The study aimed at determining the controls of the flow of water into and through these pavements, the effect of variations in construction materials and incline on them, the validity of the hydraulic testing methods currently being applied to them in industry and lastly, to inform on their infiltration rates. A host of permeability data for PICP was gained and it was found that both the choice of materials and the incline on which PICP are constructed, can change their hydraulic properties drastically. In general, the selection of lower permeability materials in the surface portion of the layer works decreased the overall permeability of the pavement, while increases in inclines did the same. In addition, it was found that field investigation techniques require revision and further innovation before they can be effectively applied to PICP. / Dissertation (MSc)--University of Pretoria, 2019. / Bosun Brick (Pty) Ltd. / Geology / MSc / Unrestricted

Compaction of urban soil where stormwater infrastructures are built reduces infiltration, vegetation growth, and stormwater treatment capacity. Biochar—a carbonaceous porous material produced by pyrolysis of organic waste – can be used as a soil amendment to improve the function of stormwater infrastructure in addition to the proven benefit of increased pollutant removal. However, the benefits depend on the biochar’s properties such as particle size distribution and concentration. Further, because biochar’s particle size distribution is altered by compaction, the hydraulic functions of compacted biochar amended soil is unknown. Herein, we examined the effect of biochar concentrations (0-6% w/w) and particle sizes (unsieved, sieved to < 2mm, and to < 0.5 mm) on water retention and saturated or unsaturated hydraulic conductivity of compacted stormwater media amended with biochar. Our results show the particle size of biochar plays a critical role in whether or not compaction is alleviated: while increasing concentration of unsieved biochar increased hydraulic conductivity up to 3% biochar, increasing concentration of fine biochar (< 2 mm) resulted in consistent decline in hydraulic conductivity under compaction. The results indicate that large biochar particles can effectively dissipate the compaction energy, while the fine biochar under compaction increased clogging by generating more fines that occupy the pores. Water retention improved regardless of the size distribution of added biochar, indicating that addition of biochar would reduce the irrigation requirement to maintain plant health in dry climate or water-stressed conditions. Overall, the results indicate that biochar addition can be effective in mitigating the negative impacts of compaction on stormwater infrastructures, depending on the proportion of coarse biochar. / Geology