Analisa-se a influência da sucção matricial e da dimensão de sapatas na capacidade de carga e nos recalques de fundações rasas, assentes em areia não-saturada. Na primeira parte da pesquisa foram analisadas 14 provas de carga estática em placas metálicas rígidas assentes a 1,5 m de profundidade, com diâmetros de 0,20, 0,40 e 0,80m e em uma sapata circular de concreto com diâmetro de 1,50 m, no campo experimental de fundações da USP/São Carlos. Devido ao caráter colapsível do solo, a sucção matricial foi monitorada por meio de tensiômetros instalados no fundo da cava. Na segunda parte da pesquisa, foram realizados ensaios em centrífuga, na Universidade do Colorado em Boulder, utilizando-se placas metálicas de 30 mm, 50 mm e 100 mm, ensaiadas a 1 g, 5 g, 10 g, 15 g, 25 g, 50 g e 100 g. As placas foram assentes em maciço de areia em três condições de umidade: seca, inundada e não-inundada. A partir dos resultados obtidos, procedeu-se a análise da capacidade de carga levando-se em conta tanto o efeito da dimensão como o da sucção matricial. A influência da dimensão nos recalques também foi analisada. Ratificou-se que o aumento da sução matricial provoca um aumento substancial na capacidade de carga do sistema placa-solo e uma diminuição considerável nos recalques. Em relação à influência da dimensão no comportamento de fundações rasas, demonstrou-se que tanto a variação da capacidade de carga como a dos recalques não ocorre de forma linear e crescente como apresentado pelos métodos teóricos. Para pequenas dimensões da sapata, os valores de capacidade de carga e recalque aumentam / The influence of matric suction and size of footings in the bearing capacity and settlement of shallow foundations in unsaturated sandy soils are analyzed. Fourteen plate load tests were performed in the first part of the research. Rigid metallic plates with diameters 0,20, 0,40, 0,80 m and one concrete circular footing with 1,50 m were used in the tests. All plates and footing were positioned at 1,50 m depth. The tests were performed in the foundation experimental field of USP/São Carlos. Due to the soil collapsible character, the tests were performed with the monitoring of matric suction pressure through tensiometers installed in the bottom of the holes. Centrifuge tests were carried out at the University of Colorado at Boulder in the second part of the research. Metallic plates with 30 mm, 50 mm and 10 mm were used and the gravity levels were 1 g, 5 g, 10 g, 15 g, 25 g, 50 g e 100 g. The plates were positioned on top of a sandy soil with three moisture conditions: dry, flooded and non-flooded. Thus, the capacity will be analyzed taking into consideration both the geometry of the tested plates and the influence of the matric suction pressure. The footing size influence in the settlement was also analyzed. A substantial increase of the plate-soil system bearing capacity and a considerable decrease in the settlements, caused by matric suction increase, was confirmed. It was also demonstrated that the bearing capacity and settlements variations are not a linearly increasing function of the size as theoretical methods suggest. For small footings, the bearing capacity and settlement increase as the footing size decreases

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-15T12:27:23Z No. of bitstreams: 1 Diogenes Virginio do Nascimento.pdf: 1474487 bytes, checksum: 048118961940a4468c5c60cb32deca19 (MD5) / Made available in DSpace on 2016-08-15T12:27:23Z (GMT). No. of bitstreams: 1 Diogenes Virginio do Nascimento.pdf: 1474487 bytes, checksum: 048118961940a4468c5c60cb32deca19 (MD5) Previous issue date: 2015-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work is related to knowledge of Pedotransfer functions (PTF), enabling an understanding about water soil content influenced by soil properties and analyzes to generate PTFs. This study aimed was proposed pedotransfer functions (PTF) based on hydro-physical soil properties and organic carbon to estimate soil moisture. The study was conducted in the area owned by Santa Teresa Plant in Goiana City, PE (7º36'56 "S 34º59'19" W) with sugarcane crop (Saccharum spp) irrigated by Lateral Move System. Field capacity (θfc) and wilting point (θwp) were assumed by dependent variables. Sand, silt, clay, soil bulk density and organic carbon were adopted as independent variables. Pedotransfer functions generated in this study estimate soil moisture to matric potential at -10 kPa, equivalent to θfc, in sandy soils and at -33 kPa to clay soils and matric potential at -1.500 kPa to θwp in 0-20; 20-40 e 40-60cm soil depth. These functions were classified as “Point PTF”, since estimated specific points to matric potential to soil water retention. Statistical indices and graphic analyses (1:1 ratio) between model-predicted and observed data were used to evaluate PTFs performance. The following statistical indices were used: Correlation coefficient (r), Concordance index (d), Maximum error (ME), Square root mean squared error normalized (RMSE), Coefficient of residual mass (CRM), Mean absolute error (MAE), Performance Index (c) and Determination coefficient (R²). Statistical indices that evaluate generated models to estimate soil water content indicated high performance for most of PTFs and good correlation between observed and estimated values at matric potential studied in all soil layers analyzed. Thus, retention water estimated by PTFs can be an interesting alternative to support irrigation management at sugarcane. / Esta dissertação é referente aos conhecimentos sobre Funções de Pedotransferência (FPT), possibilitando um entendimento relacionado ao conteúdo de água no solo a partir das influências nas propriedades do solo e nas análises estabelecidas para gerar as FPTs. O objetivo deste trabalho foi gerar funções de pedotransferência com base em atributos físico-hídricos do solo e a relação do carbono orgânico para estimar a umidade do solo. O trabalho foi realizado na área pertencente à Usina Santa Teresa localizada no município de Goiana, PE (7º36’56”S 34º59’19”W), em área cultivada com cana-de-açúcar (Saccharum spp) irrigada por sistema Lateral Móvel Linear. As variáveis adotadas como dependentes foram umidade na capacidade de campo (θcc) e umidade no ponto de murcha permanente (θpmp) e as variáveis independentes foram areia, silte, argila, densidade do solo e carbono orgânico. As funções de pedotransferência foram geradas a partir do método de regressão linear múltipla aplicando a técnica de stepwise backward elimination para seleção das variáveis candidatas ao modelo. Assim, as FPT geradas estimam o conteúdo de água no solo equilibrada nos potenciais mátricos equivalentes à umidade na capacidade de campo de -10kPa para solos arenosos, -33kPa para solos argilosos e ao ponto de murcha permanente de -1500kPa, nas camadas de 0-20; 20-40 e 40-60cm, totalizando 99 amostras. Essas funções foram classificadas como FPT pontuais, uma vez que, estima pontos específicos aplicados nas tensões de interesse para retenção de água no solo. O desempenho das Funções de pedotransferência foram analisadas graficamente pela relação 1:1, entre os dados estimados versus dados observados e por meio dos seguintes indicadores estatísticos: Coeficiente de correlação (r), Índice de concordância (d), Erro máximo (ME), Raiz quadrada do erro médio quadrático normalizado (RMSE), Coeficiente de massa residual (CRM), Erro absoluto médio (EAM), Índice de desempenho (c) e coeficiente de determinação (R²). Os índices estatísticos, que avaliam os modelos gerados para estimar a umidade volumétrica no solo estudado, apresentaram valores que indicam elevado desempenho para a maioria das FPTs e boa correlação entre os valores observados e estimados nas tensões estudadas e em todas as camadas de solo analisadas. Assim, a estimativa da retenção de água no solo por meio da FPTs apresenta-se como uma alternativa para auxiliar as técnicas adotadas no manejo de irrigação da cana-de-açúcar.

Mechanical behaviour of variably saturated clay fills VLADISLAVA KOSTKANOVÁ Ph.D. Thesis - English Abstract The excavated overburden from open-cast coal mines is end-dumped in fills. Clay type soil prevails among the filled soils in North-western Bohemia. As a consequence of the character and state of the soil, together with the mining and dumping technology, a typical lumpy structure of the clay fill is formed. The filled lumps range in size and vary in mechanical properties, but stiff to solid lumps up to 0.5 m in size are prevalent. Large and open macrovoids between the single lumps are a characteristic feature of the clay fills. Clay fills exhibit a double porosity structure, consisting of intergranular porosity between the lumps and intragranular porosity inside them. The total porosity of the freshly filled soils can reach 70%. This type of clay fill structure is metastable. This thesis focuses on the problematic behaviour of clay fill soils due to their metastable structure and their partly saturated state. Long-term monitoring of matric suction at depths up to 2 metres in two reclaimed clay fills revealed two different trends. Seasonally-dependent suction oscillations were recorded in the moderate slope of the clay fill in the Bílina mine, while no suction pointing to fully saturated conditions was...

Several hydraulic loadings impose earthen levees to time-dependent variably saturated seepage conditions. The main objective of this study is to improve the analysis of levees under transient seepage with the use of unsaturated soil mechanics. An extensive set of laboratory testing, field monitoring and numerical modeling are performed to analyze a silty sand setback levee located near Seattle, WA. In-situ data obtained from field monitoring are used to monitor suction and effective stress within the levee’s embankment and foundation over the past two years. Soil samples taken from the site are used to perform index, water retention, and unsaturated multi-stage triaxial tests in the laboratory. A finite element model of transient seepage under saturated-unsaturated conditions is then developed and calibrated to reasonably match the field data. The results highlight the need to consider unsaturated soil mechanics along with climatic variables and soil-atmosphere interaction when analyzing levees under transient seepage conditions.

The objective of this research was to investigate the effects of thermal gradient and fines content and the interaction between these two factors on the frost heave characteristics of a typical Alaska base material. The laboratory frost heave testing involved one type of aggregate base material, three thermal gradients, and three fines contents in a full-factorial experimental design with two replicates. The aggregate was classified in the American Association of State Highway and Transportation Officials soil classification system as A-1-a; the thermal gradients were 0.15, 0.30, and 0.45 ºC/cm; and the fines contents were 6, 8, and 10 percent. After frost heave testing, a stepwise regression analysis was performed to identify significant independent variables for each of nine separate dependent variables, including frost heave, heave-uptake ratio, steady-state frost heave rate, gravimetric water ingress, and gravimetric water content in each of the five individual lifts tested following frost heave testing. Soil suction, specific gravity, salinity, and hydraulic conductivity testing were also performed on samples prepared at each of the three fines contents to support numerical modeling of the frost heave test results using the computer program ICE-1. The results of the stepwise regression analysis indicate that thermal gradient is a significant predictor of six of the nine dependent variables and that the square of thermal gradient is a significant predictor of five of these six dependent variables. As the thermal gradient increased, the samples experienced decreasing amounts of water ingress and frost heave. However, the data show that neither fines content nor the square of fines content is a significant predictor of any of the dependent variables. Thus, although previous research has shown that higher fines contents are generally associated with greater susceptibility to frost heave, this effect is not manifest in the comparatively small increases in fines contents evaluated in this research. The interaction between thermal gradient and fines content is a significant predictor of only one independent variable. Differences between the modeled and measured frost heave values ranged from 0.01 to 0.92 cm, with the larger differences typically associated with the lowest thermal gradient and the lowest fines content.

[pt] O propósito do trabalho é avaliar a viabilidade técnica do uso de sondas tipo TDR e tensiômetros no monitoramento de encostas não saturadas. Com tais instrumentos, objetiva-se monitorar a variação da sucção mátrica e da umidade no solo em períodos chuvosos, visando aperfeiçoar os sistemas de alerta usados em áreas de risco e, consequentemente, minimizar perdas materiais e humanas. Para as medições, foram instalados uma estação meteorológica (munida de um pluviômetro, um datalogger, uma placa solar e uma antena para a transmissão de dados via internet), quatro sensores de umidade tipo TDR e um tensiômetro de alta capacidade em uma encosta localizada a montante da Faculdade de Medicina de Petrópolis, cidade da região serrana do estado do Rio de Janeiro. Foram registrados cerca de três meses de dados das sondas tipo TDR e, por conta de uma pane elétrica, apenas treze dias de dados do tensiômetro. As sondas tipo TDR apresentaram tempos de resposta rápidos, com nítidos aumentos de umidade volumétrica com o início de um evento chuvoso. Elas também apresentaram sensibilidade adequada para serem utilizadas em sistemas de alerta, sendo capazes de registrar alterações de umidade volumétrica com pequenos volumes de chuva. As curvas características encontradas através de ensaios de papel filtro mostraram um bom paralelo entre as sucções medidas diretamente pelo tensiômetro e aquelas obtidas indiretamente pelas sondas tipo TDR, através da conversão das umidades volumétricas em sucção. / [en] The purpose of this work is to evaluate the technical feasibility of using TDR probes and tensiometers to monitor unsaturated slopes. The objective is to monitor with these instruments the variation of matric suction and soil moisture during rainy periods, aiming to improve the warning systems used in hazardous areas and, consequently, to minimize human and material loss. For the measurements, a meteorological station (equipped with a rain gauge, a datalogger, a solar panel and an antenna for data transmission via internet), four TDR-type humidity sensors and a high capacity tensiometer were installed in a slope located in the University of Medicine of Petrópolis, city of the mountainous region of the state of Rio de Janeiro. Approximately three months of data were collected from the TDR probes and only thirteen days of tensiometer data due to a power outage. TDR-type probes showed fast response time, with clear increases in volumetric humidity with the beginning of a rainfall event. They also showed adequate sensitivity to be used in warning systems, being able to register changes in volumetric humidity with small precipitation amounts. The characteristic curves found by the filter method showed a good correlation with the suctions measured directly by the tensiometer and those obtained indirectly by the TDR probes, by converting the volumetric humidity into suction.

The investigation of the relationship between the learning culture and academic achievement is the focal point of this research. Owing to the poor scholastic performance of particularly black matric pupils in the erstwhile Department of Education and Training, an investigation was launched into the Department with a view to identify the possible causes of poor matric performance. As a point of departure an in-depth study was made into aspects of the Department of Education and Training, including those which did not fall within the ambit of the Department, which would shed light on the possible causes of poor matric results. The study revealed many signs and incidents which are symptomatic of an eroded culture of learning in a considerable number of schools. Subsequently, a comprehensive study of the establishment of a learning culture was made. According to this study the establishment of a learning culture should transcend the boundaries of the school because pupils do not only learn and study at school, but at home and in the community as well. After concluding this study it immediately became evident that a considerable number of black schools fall far short of the requirements of a learning culture. The responsibilities of the principal as the manager and instructional leader of his school, together with the selection of the principal and teachers for employment, were the next to be studied. Proper performance of the aforementioned functions as well as proper selection of either the principal or teachers for employment can contribute enormously towards establishing a positive school climate. In the empirical research data was gleaned by means of questionnaires. Thereafter the Pearson's product moment correlation coefficient was used to determine the correlation between variables and the t-test and chi-square test were used to test the null hypothesis. From the empirical investigation it emerged that there is a relationship between a learning culture and academic achievement. The ultimate conclusion reached is that the establishment of a learning culture is a prerequisite for academic achievement. Arising from this research certain conclusions were drawn, recommendations were made and areas for possible future research were suggested. / Psychology of Education / D. Ed. (Psychology of Education)

The investigation of the relationship between the learning culture and academic achievement is the focal point of this research. Owing to the poor scholastic performance of particularly black matric pupils in the erstwhile Department of Education and Training, an investigation was launched into the Department with a view to identify the possible causes of poor matric performance. As a point of departure an in-depth study was made into aspects of the Department of Education and Training, including those which did not fall within the ambit of the Department, which would shed light on the possible causes of poor matric results. The study revealed many signs and incidents which are symptomatic of an eroded culture of learning in a considerable number of schools. Subsequently, a comprehensive study of the establishment of a learning culture was made. According to this study the establishment of a learning culture should transcend the boundaries of the school because pupils do not only learn and study at school, but at home and in the community as well. After concluding this study it immediately became evident that a considerable number of black schools fall far short of the requirements of a learning culture. The responsibilities of the principal as the manager and instructional leader of his school, together with the selection of the principal and teachers for employment, were the next to be studied. Proper performance of the aforementioned functions as well as proper selection of either the principal or teachers for employment can contribute enormously towards establishing a positive school climate. In the empirical research data was gleaned by means of questionnaires. Thereafter the Pearson's product moment correlation coefficient was used to determine the correlation between variables and the t-test and chi-square test were used to test the null hypothesis. From the empirical investigation it emerged that there is a relationship between a learning culture and academic achievement. The ultimate conclusion reached is that the establishment of a learning culture is a prerequisite for academic achievement. Arising from this research certain conclusions were drawn, recommendations were made and areas for possible future research were suggested. / Psychology of Education / D. Ed. (Psychology of Education)

A cultura de soja (Glycine max (L.) Merrill) é muito importante mundialmente em função de seu uso na alimentação animal, como principal fonte de proteína e óleo, além de constituir a matéria prima básica para diversos setores da indústria. Sabe-se que a produtividade potencial de uma cultura é determinada por fatores genéticos e pelos seguintes atributos do ambiente de produção: temperatura, radiação solar, dióxido de carbono e fotoperíodo, sem restrição de água, nutrientes, plantas daninhas, pragas e doenças. A disponibilidade hídrica afeta o crescimento e desenvolvimento da cultura de soja, especialmente durante o período reprodutivo, fase de elevada atividade fisiológica. A deficiência hídrica é o principal fator limitante da produção mundial da cultura, que em sua maioria é cultivada em sistema de sequeiro em áreas com consideráveis riscos de ocorrência de deficit hídrico ao longo do ciclo da cultura. As plantas, ao longo do tempo, desenvolveram mecanismos para tolerar e/ou evitar os efeitos negativos desse estresse. O presente estudo teve como objetivo caracterizar esses mecanismos de tolerância associando-os ao potencial matricial do solo em processo de secagem. Foi avaliado a umidade gravimétrica e potencial matricial do solo, conteúdo relativo de água na folha, potencial hídrico foliar, prolina e caracteres relacionados à produção de plantas de soja, durante o período de enchimento de grãos, submetidas a três, seis, nove e doze dias sem irrigação, comparados com o controle irrigado diariamente. De acordo com o observado, os mecanismos de tolerância da soja à deficiência hídrica foram satisfatórios para a manutenção do conteúdo relativo de água e potencial hídrico foliar em níveis adequados até o valor de potencial matricial de água no solo de -0,8 atm, tendo a prolina papel importante nesse mecanismo. As avaliações hídricas, conteúdo relativo de água e potencial foliar se mostraram relacionados com a manutenção da produtividade de soja sob situação de deficiência hídrica, mostrando-se adequados para o estudo de tolerância de cultivares de soja à restrição hídrica. / Soybean crop (Glycine max (L.) Merrill) is very important worldwide because it is used in animal feeding, a source of protein and oil, and also raw material for many manufactured goods. It is known that a crop potential yield is determined by genetic factors and by the following production environment characteristics: temperature, solar radiation, carbon dioxide, photoperiod, water availability, nutrients, weeds, pests and diseases. Water availability affects soybean growth and development especially during the reproductive phase which has high physiological activity. Water deficit is a key factor on world`s soybean production which is generally grown in dry land systems with considerable high risks of water deficit along soybean crop season. Plants have developed mechanisms over time to tolerate and/or avoid negative effects of this kind of stress. The present study had as the main goal to characterize these mechanisms of tolerance associating them with soil matric potential of a soil in a drying process. It was assessed the gravimetrical humidity and soil matric potential, leaf relative water content, leaf water potential, proline and yield component of plants under three, six, nine and twelve days without irrigation during grain filling phase. In accordance with the observed, soybean water deficit tolerance mechanisms were enough to maintain leaf relative water content and leaf water potential at acceptable levels until soil matric potential were around -0.8 atm, which proline was a key factor in this mechanism. Leaf relative water content and leaf water potential showed to be related in maintaining soybean yield under water deficit and they may be used in studies of soybean tolerant cultivars to water restriction.

A cultura de soja (Glycine max (L.) Merrill) é muito importante mundialmente em função de seu uso na alimentação animal, como principal fonte de proteína e óleo, além de constituir a matéria prima básica para diversos setores da indústria. Sabe-se que a produtividade potencial de uma cultura é determinada por fatores genéticos e pelos seguintes atributos do ambiente de produção: temperatura, radiação solar, dióxido de carbono e fotoperíodo, sem restrição de água, nutrientes, plantas daninhas, pragas e doenças. A disponibilidade hídrica afeta o crescimento e desenvolvimento da cultura de soja, especialmente durante o período reprodutivo, fase de elevada atividade fisiológica. A deficiência hídrica é o principal fator limitante da produção mundial da cultura, que em sua maioria é cultivada em sistema de sequeiro em áreas com consideráveis riscos de ocorrência de deficit hídrico ao longo do ciclo da cultura. As plantas, ao longo do tempo, desenvolveram mecanismos para tolerar e/ou evitar os efeitos negativos desse estresse. O presente estudo teve como objetivo caracterizar esses mecanismos de tolerância associando-os ao potencial matricial do solo em processo de secagem. Foi avaliado a umidade gravimétrica e potencial matricial do solo, conteúdo relativo de água na folha, potencial hídrico foliar, prolina e caracteres relacionados à produção de plantas de soja, durante o período de enchimento de grãos, submetidas a três, seis, nove e doze dias sem irrigação, comparados com o controle irrigado diariamente. De acordo com o observado, os mecanismos de tolerância da soja à deficiência hídrica foram satisfatórios para a manutenção do conteúdo relativo de água e potencial hídrico foliar em níveis adequados até o valor de potencial matricial de água no solo de -0,8 atm, tendo a prolina papel importante nesse mecanismo. As avaliações hídricas, conteúdo relativo de água e potencial foliar se mostraram relacionados com a manutenção da produtividade de soja sob situação de deficiência hídrica, mostrando-se adequados para o estudo de tolerância de cultivares de soja à restrição hídrica. / Soybean crop (Glycine max (L.) Merrill) is very important worldwide because it is used in animal feeding, a source of protein and oil, and also raw material for many manufactured goods. It is known that a crop potential yield is determined by genetic factors and by the following production environment characteristics: temperature, solar radiation, carbon dioxide, photoperiod, water availability, nutrients, weeds, pests and diseases. Water availability affects soybean growth and development especially during the reproductive phase which has high physiological activity. Water deficit is a key factor on world`s soybean production which is generally grown in dry land systems with considerable high risks of water deficit along soybean crop season. Plants have developed mechanisms over time to tolerate and/or avoid negative effects of this kind of stress. The present study had as the main goal to characterize these mechanisms of tolerance associating them with soil matric potential of a soil in a drying process. It was assessed the gravimetrical humidity and soil matric potential, leaf relative water content, leaf water potential, proline and yield component of plants under three, six, nine and twelve days without irrigation during grain filling phase. In accordance with the observed, soybean water deficit tolerance mechanisms were enough to maintain leaf relative water content and leaf water potential at acceptable levels until soil matric potential were around -0.8 atm, which proline was a key factor in this mechanism. Leaf relative water content and leaf water potential showed to be related in maintaining soybean yield under water deficit and they may be used in studies of soybean tolerant cultivars to water restriction.