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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Determinação de módulos de deformabilidade através de provas de carga no cone elétrico / Determination of soil deformability moduli from cone loading tests

Salles, Jude Christian 27 September 2013 (has links)
O desempenho das fundações pode ser avaliado da maneira clássica através de provas de carga estáticas ou dinâmicas. Estas provas de carga são, em geral, caras e demoradas, além de que é necessário que o elemento de fundação já esteja pronto. Outra forma de avaliar o desempenho de fundações é determinar os parâmetros de deformabilidade do solo, em especial os módulos de deformabilidade. Em geral, esses módulos são estimados através de correlações empíricas com o N do SPT ou qc do CPT. Poucas vezes ensaios de laboratório (como o triaxial), ou especiais de campo (como o pressiômetro), são executados para determinação desse parâmetro. Uma possibilidade de contornar esse problema é realizar uma prova de carga no cone elétrico (o ensaio CLT) simultaneamente ao ensaio CPT. Neste trabalho apresenta-se como o ensaio CLT pode ser realizado e como seu resultado pode ser interpretado. Uma campanha de ensaios CLT foi realizada no campo experimental da Unesp de Bauru. Os resultados desses ensaios foram utilizados para calcular o módulo ECLT na região elástica linear inicial da curva, de modo similar como se determina o módulo de Young para o aço. Os valores dos módulos ECLT foram comparados com os módulos de deformabilidade determinados a partir de ensaios de pressiômetro. Também foi possível representar a curva de degradação do módulo de cisalhamento para o local estudado. Apresenta-se também a correlação obtida para estimativa de ECLT a partir dos valores da resistência de ponta do cone (qc) para os solos da área estudada. Conclui-se que o ensaio CLT é uma técnica rápida e econômica que pode ser utilizada como um complemento ao ensaio CPT para um melhor entendimento do comportamento tensão-deformação do solo. Com o ensaio CLT é possível estimar um parâmetro de deformabilidade, o ECLT, bem como representar a degradação do módulo com o nível de deformação. Este ensaio híbrido, CPT+CLT, tem potencial para uso na investigação de solos não convencionais, onde quase sempre não existem parâmetros de referência para estimativa de recalques de fundações. / The performance of foundations can be evaluated the classical way, through static and dynamic load tests. Such load tests are generally time-consuming and expensive, besides that it is necessary that the foundation system be already in place. Another way to evaluate the performance of foundations is to determine the deformability parameters of the soil, especially the the deformability moduli. Ordinarily such moduli are estimated through empirical correlations with N of SPT or qc of CPT. Seldom laboratory tests (such as the triaxial) and field tests (such as the pressiometer) are employed to determine such parameters. One way to solve this problem is to perform a load test on the electric cone (the Cone Loading Test) simultaneously with the CPT test. The work presented here shows how the Cone Loading Test (CLT) can be performed and how its results can be interpreted. A campaign of Cone Loading Tests was conducted at the research site of Unesp-Bauru, São Paulo, Brazil. The CLT results were used to calculate the modulus ECLT in the linear elastic region of the stress-strain curve, in the same manner how the modulus of Young for steel is obtained. The values for ECLT moduli were compared to the deformability moduli obtained from pressiometer (PMT) tests. It was also possible to generate the degradation curve for shear modulus of the soil in the area of study. Presented here are the correlations obtained in the estimation of ECLT from values of cone tip resistance (qc) for the studied soils. From the results obtained, it can be concluded CLT is a fast and inexpensive technique that can be used as a complement to the CPT in improving the understanding of the stress-strain behavior of soils. With CLT it is possible to estimate the deformability parameter ECLT, as well as to represent the degradation of the modulus with increasing levels of strain. Such a hybrid test, CPT+CLT, has potential use in the investigation of non-conventional soils, which lack reference parameters for the estimation os settlement of foundations installed in them.
12

Integração de diferentes técnicas de investigação para avaliação da poluição e contaminação de uma área de disposição de resíduos sólidos urbanos / Integration of different site investigation techniques to assess pollution and contamination in a municipal solid waste disposal site

Mondelli, Giulliana 03 October 2008 (has links)
Nos últimos anos, a preocupação com a poluição e a contaminação do subsolo provocadas pela disposição de resíduos sólidos urbanos ou industriais tem crescido no Brasil, principalmente no que diz respeito aos lixões e aterros controlados em operação ou desativados na maioria das cidades brasileiras de pequeno e médio porte. A tese apresenta os resultados de diversas campanhas de investigação realizadas no aterro de resíduos sólidos urbanos de Bauru, situado no centro do Estado de São Paulo e sobre o aqüífero Bauru, que aflora em cerca da metade de todo o território paulista. O objetivo foi avaliar a poluição e a contaminação do entorno e do subsolo do aterro, através da utilização de diferentes técnicas de investigação. Entre as técnicas utilizadas, incluem-se: geofísica de superfície, poços de monitoramento, piezocone (CPTU), piezocone de resistividade (RCPTU) e amostragem de solo e água. Ensaios de laboratório de caracterização, resistividade elétrica e com percolação de chorume em amostras indeformadas de solo foram realizados para confirmar e entender melhor o caminhamento e a interação das plumas de contaminação com o meio. Uma revisão de todas as informações prévias sobre as características físicas, hidrogeológicas e de operação do aterro, desde sua implantação, em 1992, foi fundamental para a escolha dos locais para realização dos novos ensaios de campo e re-interpretação dos mesmos. As principais contribuições são: a) Aplicação de novas técnicas de investigação em solos tropicais contaminados; b) Desenvolvimento de um sistema em laboratório para estimativa de parâmetros de transporte de poluentes e para medida de resistividade elétrica em solos tropicais; c) Avaliação da resistividade elétrica como uma ferramenta promissora para investigação geoambiental; d) Avaliação da contaminação e da poluição no aterro a partir de diferentes técnicas de investigação; e) Orientação e sugestões para realização de futuras investigações, sejam na área de estudo ou em outros solos tropicais. Os ensaios geofísicos facilitaram a visualização da dimensão espacial e a detecção dos sentidos das plumas de contaminação existentes na área. Os ensaios de piezocone confirmaram essa contaminação em alguns pontos, utilizando-se amostradores especiais de solo e água. As campanhas de coleta de água dos poços de monitoramento permitiram avaliar a evolução da pluma de contaminação com o tempo. As medidas de resistividade em laboratório possibilitaram definir valores de referência para os solos do aterro, confirmando a grande influência exercida pela mineralogia, intemperismo e grau de evolução dos solos tropicais nos valores de resistividade. Os elevados valores de permeabilidade e dispersividade explicam o aparecimento de mais de uma pluma de contaminação na área: uma principal e permanente a oeste; uma ao sul do aterro, na região de disposição dos resíduos hospitalares; uma a leste do sentido do fluxo subterrâneo, que sofria influencia dos elevados níveis piezométricos de chorume dentro da massa de lixo; e pontos de contaminação centrais, que ocorrem abaixo e a grandes profundidades da base do aterro. Os resultados confirmaram a importância de se integrar diferentes técnicas de investigação geoambiental, diretas e indiretas, para melhor avaliar casos de contaminação e poluição em solos tropicais, de gênese e comportamento complexos, e presentes em grande parte do território brasileiro. Propostas para melhoramento e realização de futuros ensaios na área, assim como de ordem prática para recuperação, monitoramento e operação do aterro são apresentadas, a fim de melhorar a qualidade das condições in situ locais. / For the last years, the concern about pollution and contamination of the soil and groundwater caused by the industrial and municipal solid waste disposal sites has increased in Brazil. Due to the non-application of the environmental guidelines for landfill construction and operation, dumps and controlled dumps in operation or deactivated, located in small and medium-size brazilian cities, have called the attention about this problem. This Thesis presents the results of several tests carried out at the Bauru\'s municipal solid waste disposal site, located in the center of São Paulo State and above the Bauru\'s aquifer, which appears at approximately half São Paulo State superficial area. The main objective was to assess the pollution and contamination caused by this landfill, using different techniques for geoenvironmental site investigation. These techniques included: superficial geophysics, monitoring wells, piezocone (CPTU), resistivity piezocone (RCPTU) and soil and water sampling. Laboratory tests including characterization, electrical resistivity measurements and pollutant transport in undisturbed soil samples were conducted to verify and to better understand the contamination plumes pathways and their interaction with the environmental site. A review of all existing data about the site, hydrogeological characteristics and operation of the landfill, since it was idealized in 1992, were also important for a better selection of new in situ tests and (re) interpretation of them. The main contributions are: a) Application of new site investigation techniques in contaminated tropical soils; b) Development of a system in laboratory for pollutants transport parameters estimation and electrical resistivity measurements in tropical soils; c) Evaluation of the electrical resistivity measures as a promising tool for geoenvironmental researches; d) Pollution and contamination assessment of the site based on the different techniques; e) Directions and suggestions for future site investigations at the study site or in other tropical areas. The geophysical tests facilitated the visualization of the spatial distribution and directions of the local contamination plumes. The piezocone tests confirmed this contamination in some local spots, supported by special soil and water samplers. Numerous groundwater samples collected from the permanent monitoring wells allowed the assessment of the contamination plumes evolution as time passed by. The resistivity measurements in laboratory detected background resistivity values for the local soils, confirming the great influence of the mineralogy, weathering and degree of evolution of the tropical soils. The high permeability and dispersivity values explain the occurrence of more than one contamination plume at the site: a principal and permanent plume located to the west side; on the south of the landfill, where medical wastes were disposed; to the east side of the groundwater flow, caused by the high piezometric leachate levels inside the landfill; and some central spots of contamination occurring below and deep inside the landfill. The results confirmed the importance of the integration of different techniques for geoenvironmental site investigation, using direct and indirect methods to better understand the contamination and pollution in tropical soils, which have complex genesis and behavior, and take place in a great part of the brazilian territory. Practical proposals to improve and carry out new tests at the site, as well as for recovering plans, monitoring and operation of the landfill are presented in order to improve the local in situ conditions.
13

Determinação de módulos de deformabilidade através de provas de carga no cone elétrico / Determination of soil deformability moduli from cone loading tests

Jude Christian Salles 27 September 2013 (has links)
O desempenho das fundações pode ser avaliado da maneira clássica através de provas de carga estáticas ou dinâmicas. Estas provas de carga são, em geral, caras e demoradas, além de que é necessário que o elemento de fundação já esteja pronto. Outra forma de avaliar o desempenho de fundações é determinar os parâmetros de deformabilidade do solo, em especial os módulos de deformabilidade. Em geral, esses módulos são estimados através de correlações empíricas com o N do SPT ou qc do CPT. Poucas vezes ensaios de laboratório (como o triaxial), ou especiais de campo (como o pressiômetro), são executados para determinação desse parâmetro. Uma possibilidade de contornar esse problema é realizar uma prova de carga no cone elétrico (o ensaio CLT) simultaneamente ao ensaio CPT. Neste trabalho apresenta-se como o ensaio CLT pode ser realizado e como seu resultado pode ser interpretado. Uma campanha de ensaios CLT foi realizada no campo experimental da Unesp de Bauru. Os resultados desses ensaios foram utilizados para calcular o módulo ECLT na região elástica linear inicial da curva, de modo similar como se determina o módulo de Young para o aço. Os valores dos módulos ECLT foram comparados com os módulos de deformabilidade determinados a partir de ensaios de pressiômetro. Também foi possível representar a curva de degradação do módulo de cisalhamento para o local estudado. Apresenta-se também a correlação obtida para estimativa de ECLT a partir dos valores da resistência de ponta do cone (qc) para os solos da área estudada. Conclui-se que o ensaio CLT é uma técnica rápida e econômica que pode ser utilizada como um complemento ao ensaio CPT para um melhor entendimento do comportamento tensão-deformação do solo. Com o ensaio CLT é possível estimar um parâmetro de deformabilidade, o ECLT, bem como representar a degradação do módulo com o nível de deformação. Este ensaio híbrido, CPT+CLT, tem potencial para uso na investigação de solos não convencionais, onde quase sempre não existem parâmetros de referência para estimativa de recalques de fundações. / The performance of foundations can be evaluated the classical way, through static and dynamic load tests. Such load tests are generally time-consuming and expensive, besides that it is necessary that the foundation system be already in place. Another way to evaluate the performance of foundations is to determine the deformability parameters of the soil, especially the the deformability moduli. Ordinarily such moduli are estimated through empirical correlations with N of SPT or qc of CPT. Seldom laboratory tests (such as the triaxial) and field tests (such as the pressiometer) are employed to determine such parameters. One way to solve this problem is to perform a load test on the electric cone (the Cone Loading Test) simultaneously with the CPT test. The work presented here shows how the Cone Loading Test (CLT) can be performed and how its results can be interpreted. A campaign of Cone Loading Tests was conducted at the research site of Unesp-Bauru, São Paulo, Brazil. The CLT results were used to calculate the modulus ECLT in the linear elastic region of the stress-strain curve, in the same manner how the modulus of Young for steel is obtained. The values for ECLT moduli were compared to the deformability moduli obtained from pressiometer (PMT) tests. It was also possible to generate the degradation curve for shear modulus of the soil in the area of study. Presented here are the correlations obtained in the estimation of ECLT from values of cone tip resistance (qc) for the studied soils. From the results obtained, it can be concluded CLT is a fast and inexpensive technique that can be used as a complement to the CPT in improving the understanding of the stress-strain behavior of soils. With CLT it is possible to estimate the deformability parameter ECLT, as well as to represent the degradation of the modulus with increasing levels of strain. Such a hybrid test, CPT+CLT, has potential use in the investigation of non-conventional soils, which lack reference parameters for the estimation os settlement of foundations installed in them.
14

Emprego do ensaio SPT sísmico na investigação de solos tropicais / The use of seismic SPT test for site investigation of tropical soils

Breno Padovezi Rocha 30 August 2013 (has links)
O principal objetivo deste trabalho é avaliar a aplicação da técnica híbrida de SPT Sísmico (S-SPT), ou seja, a realização da sísmica up-hole em conjunto com a sondagem de simples reconhecimento com medida de SPT, para uma melhor caracterização de solos tropicais. O ensaio híbrido mais empregado para determinação de parâmetros dos solos, inclusive o módulo de cisalhamento máximo (Go) é o de cone sísmico (SCPT). No entanto, sua realização exige equipamentos especiais e de custo elevado. A possibilidade de medir a velocidade de propagação da onda S (VS) em conjunto com o ensaio SPT empregando o a técnica up-hole é uma alternativa interessante. Essa técnica combinada, pouco empregada no Brasil, foi recentemente desenvolvida e testada. Neste trabalho, a determinação ao mesmo tempo e no mesmo furo dos valores de N do SPT e velocidade de onda S (Vs) permitiu calcular o módulo de cisalhamento máximo (Go) e avaliar as vantagens de se obter a relação Go/N, similar a relação entre Go/qc, para investigação de solos tropicais colapsíveis. As áreas de estudo são os campos experimentais da UNESP-Bauru, USP-São Carlos e UNICAMP-Campinas, onde ensaios S-SPT foram realizados. Os resultados desses ensaios foram comparados com valores de VS referência, determinados através de ensaios sísmicos cross-hole, down-hole e SCPT. A diferença entre os valores de VS foram, em média, 8,5, 9,0% e 16,0% respectivamente para os campos experimentais da UNESP-Bauru, USP-São Carlos e UNICAMP-Campinas. Considera-se que a técnica híbrida do S-SPT pode ser empregada para obter o perfil de Go, em conjunto com o ensaio SPT, rapidamente e a um custo relativamente baixo. Constatou-se que a relação Go/N é maior na camada de solo laterítico, e que ela diminui quanto menos evoluído é o perfil do subsolo. Observou-se essa a mesma tendência nos ensaios S-SPT, porém com menor nitidez. Este fato pode estar associado a maior dificuldade de interpretar os registros de ondas sísmicas pela técnica up-hole bem como pela variabilidade do perfil dos subsolos. / The main objective of this work is to assess the applicability of the hybrid test, the Seismic SPT (S-SPT), i.e. the up-hole seismic test carried out together with SPT test, in order to achieve a better site characterization of tropical soils. The most used hybrid test to determine the soil parameters, including the maximum shear modulus (Go), is the seismic cone test (SCPT). The possibility of measuring the S wave velocity together with the SPT test using the up-hole technique is an interesting alternative. This combined technique was scarcely used in Brazil and it has been recently developed and tested. In this work, the concomitant measuring of the SPT N value together with the S wave velocity in the same test allowed calculating the maximum shear modulus (Go) and assessing the advantages of obtaining the Go/N ratio, similar to the Go/qc ratio, for the site characterization of tropical collapsible soils. The research areas are the experimental sites of UNESP-Bauru, USP-São Carlos and UNICAMP-Campinas, where SPT tests were carried out. The results of these tests were compared with reference values VS, which were determined via cross-hole, down-hole and SCPT tests. The differences between VS values were, in average, 8.5%, 9.0% and 16.0% respectively for UNESP-Bauru, USP-São Carlos and Campinas-UNICAMP research sites. The hybrid S-SPT test can be used to define the Go profile, together with the N SPT values, with a relatively low cost. It was found that the Go/N ratio is higher in the lateritic soil layer and it gets lower as the soil profile is less developed. The same tendency was observed with the S-SPT tests, however with less distinctness. This fact can be associated to a higher difficulty on the interpretation of seismic wave traces with the up-hole technique as well as to soil variability.
15

Integração de diferentes técnicas de investigação para avaliação da poluição e contaminação de uma área de disposição de resíduos sólidos urbanos / Integration of different site investigation techniques to assess pollution and contamination in a municipal solid waste disposal site

Giulliana Mondelli 03 October 2008 (has links)
Nos últimos anos, a preocupação com a poluição e a contaminação do subsolo provocadas pela disposição de resíduos sólidos urbanos ou industriais tem crescido no Brasil, principalmente no que diz respeito aos lixões e aterros controlados em operação ou desativados na maioria das cidades brasileiras de pequeno e médio porte. A tese apresenta os resultados de diversas campanhas de investigação realizadas no aterro de resíduos sólidos urbanos de Bauru, situado no centro do Estado de São Paulo e sobre o aqüífero Bauru, que aflora em cerca da metade de todo o território paulista. O objetivo foi avaliar a poluição e a contaminação do entorno e do subsolo do aterro, através da utilização de diferentes técnicas de investigação. Entre as técnicas utilizadas, incluem-se: geofísica de superfície, poços de monitoramento, piezocone (CPTU), piezocone de resistividade (RCPTU) e amostragem de solo e água. Ensaios de laboratório de caracterização, resistividade elétrica e com percolação de chorume em amostras indeformadas de solo foram realizados para confirmar e entender melhor o caminhamento e a interação das plumas de contaminação com o meio. Uma revisão de todas as informações prévias sobre as características físicas, hidrogeológicas e de operação do aterro, desde sua implantação, em 1992, foi fundamental para a escolha dos locais para realização dos novos ensaios de campo e re-interpretação dos mesmos. As principais contribuições são: a) Aplicação de novas técnicas de investigação em solos tropicais contaminados; b) Desenvolvimento de um sistema em laboratório para estimativa de parâmetros de transporte de poluentes e para medida de resistividade elétrica em solos tropicais; c) Avaliação da resistividade elétrica como uma ferramenta promissora para investigação geoambiental; d) Avaliação da contaminação e da poluição no aterro a partir de diferentes técnicas de investigação; e) Orientação e sugestões para realização de futuras investigações, sejam na área de estudo ou em outros solos tropicais. Os ensaios geofísicos facilitaram a visualização da dimensão espacial e a detecção dos sentidos das plumas de contaminação existentes na área. Os ensaios de piezocone confirmaram essa contaminação em alguns pontos, utilizando-se amostradores especiais de solo e água. As campanhas de coleta de água dos poços de monitoramento permitiram avaliar a evolução da pluma de contaminação com o tempo. As medidas de resistividade em laboratório possibilitaram definir valores de referência para os solos do aterro, confirmando a grande influência exercida pela mineralogia, intemperismo e grau de evolução dos solos tropicais nos valores de resistividade. Os elevados valores de permeabilidade e dispersividade explicam o aparecimento de mais de uma pluma de contaminação na área: uma principal e permanente a oeste; uma ao sul do aterro, na região de disposição dos resíduos hospitalares; uma a leste do sentido do fluxo subterrâneo, que sofria influencia dos elevados níveis piezométricos de chorume dentro da massa de lixo; e pontos de contaminação centrais, que ocorrem abaixo e a grandes profundidades da base do aterro. Os resultados confirmaram a importância de se integrar diferentes técnicas de investigação geoambiental, diretas e indiretas, para melhor avaliar casos de contaminação e poluição em solos tropicais, de gênese e comportamento complexos, e presentes em grande parte do território brasileiro. Propostas para melhoramento e realização de futuros ensaios na área, assim como de ordem prática para recuperação, monitoramento e operação do aterro são apresentadas, a fim de melhorar a qualidade das condições in situ locais. / For the last years, the concern about pollution and contamination of the soil and groundwater caused by the industrial and municipal solid waste disposal sites has increased in Brazil. Due to the non-application of the environmental guidelines for landfill construction and operation, dumps and controlled dumps in operation or deactivated, located in small and medium-size brazilian cities, have called the attention about this problem. This Thesis presents the results of several tests carried out at the Bauru\'s municipal solid waste disposal site, located in the center of São Paulo State and above the Bauru\'s aquifer, which appears at approximately half São Paulo State superficial area. The main objective was to assess the pollution and contamination caused by this landfill, using different techniques for geoenvironmental site investigation. These techniques included: superficial geophysics, monitoring wells, piezocone (CPTU), resistivity piezocone (RCPTU) and soil and water sampling. Laboratory tests including characterization, electrical resistivity measurements and pollutant transport in undisturbed soil samples were conducted to verify and to better understand the contamination plumes pathways and their interaction with the environmental site. A review of all existing data about the site, hydrogeological characteristics and operation of the landfill, since it was idealized in 1992, were also important for a better selection of new in situ tests and (re) interpretation of them. The main contributions are: a) Application of new site investigation techniques in contaminated tropical soils; b) Development of a system in laboratory for pollutants transport parameters estimation and electrical resistivity measurements in tropical soils; c) Evaluation of the electrical resistivity measures as a promising tool for geoenvironmental researches; d) Pollution and contamination assessment of the site based on the different techniques; e) Directions and suggestions for future site investigations at the study site or in other tropical areas. The geophysical tests facilitated the visualization of the spatial distribution and directions of the local contamination plumes. The piezocone tests confirmed this contamination in some local spots, supported by special soil and water samplers. Numerous groundwater samples collected from the permanent monitoring wells allowed the assessment of the contamination plumes evolution as time passed by. The resistivity measurements in laboratory detected background resistivity values for the local soils, confirming the great influence of the mineralogy, weathering and degree of evolution of the tropical soils. The high permeability and dispersivity values explain the occurrence of more than one contamination plume at the site: a principal and permanent plume located to the west side; on the south of the landfill, where medical wastes were disposed; to the east side of the groundwater flow, caused by the high piezometric leachate levels inside the landfill; and some central spots of contamination occurring below and deep inside the landfill. The results confirmed the importance of the integration of different techniques for geoenvironmental site investigation, using direct and indirect methods to better understand the contamination and pollution in tropical soils, which have complex genesis and behavior, and take place in a great part of the brazilian territory. Practical proposals to improve and carry out new tests at the site, as well as for recovering plans, monitoring and operation of the landfill are presented in order to improve the local in situ conditions.
16

Previsão da curva tensão-recalque em solos tropicais arenosos a partir de ensaios de cone sísmico / Prediction of stress-settlement curve on tropical sandy soils based on seismic cone test

Tiago de Jesus Souza 19 September 2011 (has links)
Apresenta-se neste trabalho a aplicação de um método para a previsão da curva tensão-recalque de fundações diretas assentes em solos tropicais arenosos a partir de resultados de ensaios de cone sísmico (SCPT). Os locais estudados foram os campos experimentais de fundações da EESC/USP - São Carlos e da UNESP-Bauru, onde existem resultados de provas de carga realizados a diferentes profundidades, assim como resultados de ensaios SCPT. As previsões realizadas apresentaram bons resultados, após ajustes dos parâmetros f e g, pois as curvas tensão-recalque estimadas foram próximas a aquelas obtidas a partir de provas de carga em placa, para as profundidades maiores que 1,5 metros. Verifica-se assim a aplicabilidade do método, após seu ajuste, para reproduzir a curva tensão-recalque neste tipo de solo, empregando uma abordagem mais racional, com menor dependência de correlações empíricas. Destaca-se nesta pesquisa que existe uma variabilidade dos resultados de ensaios SCPT e de provas de carga que está relacionada com a mudança de sucção no solo. Para o campo experimental de São Carlos foi possível ainda fazer uma avaliação da variabilidade nas previsões realizadas, pois existe maior número de resultados de ensaios de campo e provas de cargas disponíveis. / It is presented in this dissertation the use of a method for predicting the stress-settlement curve of shallow foundations on tropical sandy soils based on seismic cone (SCPT) test results. The studied sites were the experimental research sites from USP - São Carlos, and UNESP - Bauru, Brazil, where there are results from plate load tests conducted at various depths, as well as SCPT test results. The stress-settlement curve predictions show good results, after adjusting the parameters f and g, because the estimated curves were close to those obtained from plate load tests, to depths greater than 1.5 meters. The applicability of the method, after its adjustment, to reproduce the stress-settlement curve for this type of soil, was verified employing a more rational approach with less reliance on empirical correlations. It is highlighted in this research that there is variability on SCPT and plate load test results, which is related to the change in soil suction. It was also possible to access the variability on the prediction for the USP São Carlos site, since there is a greater number of in situ and plate load tests in this site.
17

[pt] CARACTERIZAÇÃO E AVALIAÇÃO DA CONTAMINAÇÃO DAS ÁGUAS SUBTERRÂNEAS POR METAIS PESADOS DA ÁREA DE DISPOSIÇÃO DE RESÍDUOS DE RESENDE, RJ / [en] CHARACTERIZATION AND EVALUATION OF GROUNDWATER CONTAMINATION DUE TO HEAVY METALS IN A WASTE DISPOSAL AREA IN RESENDE, RJ

CRISTINA KEI YAMAMOTO DE OLIVEIRA 07 April 2022 (has links)
[pt] O objetivo deste trabalho é avaliar a contaminação da água subterrânea por metais pesados provenientes da Área de Disposição de Resíduos (ADR) do município de Resende, RJ. O escopo compreende um estudo preliminar com base em levantamento e mapeamento de dados espaciais; investigação in situ e em laboratório, incluindo a instalação de poços de monitoramento, amostragens e caracterização de solos, águas subterrâneas e chorume, ensaios de condutividade hidráulica, K; e modelagem da pluma de contaminação usando o programa MIKE SHE. Em geral, a caracterização apresentou argilas arenosas, siltes arenosos e, areias siltosas, cujos principais minerais foram quartzo, caulinita, e muscovita com presença de biotita e feldspato. Os valores de K variaram de 10(-5) a 10(-6) m/s; o pH entre 4,59 e 6,93 (água subterrânea) e 7,93 e 8,16 (chorume); a condutividade elétrica na água variou de 0,032 a 7,113 mS/cm, coerente com os sólidos totais dissolvidos e com maiores valores no chorume e no poço mais próximo a ADR. Análises detectaram 14 metais dissolvidos (Al, As, B, Ba, Cd, Co, Cr, Fe, Hg, Mn, Ni, Pb, Se e Zn) em concentrações acima do permissível por lei. A modelagem mostrou como a distribuição espacial e a anisotropia dos solos influenciam o fluxo e transporte do cloreto (advectivo) e do cromo (sorção). Quando são considerados solos anisotrópicos, a pluma de Cl- atinge o Rio Paraíba do Sul, à 2,5 km de distância, em 43 anos enquanto a pluma do Cr dista apenas 55 m da fonte. Embora os resultados experimentais não tenham sido claros em determinar se todos os metais encontrados são necessariamente da fonte de contaminação da ADR ou de origens naturais, as simulações deste modelo indicaram baixo impacto ambiental dos metais para o rio. / [en] The objective of this work is to evaluate the groundwater contamination due to heavy metals from the Waste Disposal Area (WDA) in the municipality of Resende, RJ. The scope consists of a preliminary assessment based on surveying and mapping spatial data; in situ and laboratory investigation, including the installation of monitoring wells, sampling and characterization of soils, groundwater and waste leachate, hydraulic conductivity tests, K; and contaminant plume modelling using the program MIKE SHE. Overall, the characterization revealed sandy clays, sandy silts and silty sands. The predominant minerals were quartz, kaolinite, and muscovite along with the presence of biotite and feldspar. The values of K varied from 10(-5) to 10(-6) m/s; the pH between 4.59 and 6.93 (groundwater) and 7.93 and 8.16 (leachate); the electrical conductivity in the water varied from 0.032 to 7.113 mS/cm, consistent with the total dissolved solids and with higher values attributed to the leachate and the well closest to the WDA. Analysis detected 14 dissolved metals (Al, As, B, Ba, Cd, Co, Cr, Fe, Hg, Mn, Ni, Pb, Se and Zn) with concentrations above the legal limit. The model illustrated how the soils spatial distribution and anisotropy influence the flow and transport of chloride (advective) and chromium (sorption). When considering anisotropic soils, the Clplume reached the Paraíba do Sul River, 2.5 km away, in 43 years while the Cr plume only moved 55 m from the source. Although the experimental results were not clear in determining whether all the metals found necessarily originated from the contaminant source from the WDA or from natural origins, the simulations of this model indicated a low environmental impact to the river.
18

Geotechnical Site Characterization And Liquefaction Evaluation Using Intelligent Models

Samui, Pijush 02 1900 (has links)
Site characterization is an important task in Geotechnical Engineering. In situ tests based on standard penetration test (SPT), cone penetration test (CPT) and shear wave velocity survey are popular among geotechnical engineers. Site characterization using any of these properties based on finite number of in-situ test data is an imperative task in probabilistic site characterization. These methods have been used to design future soil sampling programs for the site and to specify the soil stratification. It is never possible to know the geotechnical properties at every location beneath an actual site because, in order to do so, one would need to sample and/or test the entire subsurface profile. Therefore, the main objective of site characterization models is to predict the subsurface soil properties with minimum in-situ test data. The prediction of soil property is a difficult task due to the uncertainities. Spatial variability, measurement ‘noise’, measurement and model bias, and statistical error due to limited measurements are the sources of uncertainities. Liquefaction in soil is one of the other major problems in geotechnical earthquake engineering. It is defined as the transformation of a granular material from a solid to a liquefied state as a consequence of increased pore-water pressure and reduced effective stress. The generation of excess pore pressure under undrained loading conditions is a hallmark of all liquefaction phenomena. This phenomena was brought to the attention of engineers more so after Niigata(1964) and Alaska(1964) earthquakes. Liquefaction will cause building settlement or tipping, sand boils, ground cracks, landslides, dam instability, highway embankment failures, or other hazards. Such damages are generally of great concern to public safety and are of economic significance. Site-spefific evaluation of liquefaction susceptibility of sandy and silty soils is a first step in liquefaction hazard assessment. Many methods (intelligent models and simple methods as suggested by Seed and Idriss, 1971) have been suggested to evaluate liquefaction susceptibility based on the large data from the sites where soil has been liquefied / not liquefied. The rapid advance in information processing systems in recent decades directed engineering research towards the development of intelligent models that can model natural phenomena automatically. In intelligent model, a process of training is used to build up a model of the particular system, from which it is hoped to deduce responses of the system for situations that have yet to be observed. Intelligent models learn the input output relationship from the data itself. The quantity and quality of the data govern the performance of intelligent model. The objective of this study is to develop intelligent models [geostatistic, artificial neural network(ANN) and support vector machine(SVM)] to estimate corrected standard penetration test (SPT) value, Nc, in the three dimensional (3D) subsurface of Bangalore. The database consists of 766 boreholes spread over a 220 sq km area, with several SPT N values (uncorrected blow counts) in each of them. There are total 3015 N values in the 3D subsurface of Bangalore. To get the corrected blow counts, Nc, various corrections such as for overburden stress, size of borehole, type of sampler, hammer energy and length of connecting rod have been applied on the raw N values. Using a large database of Nc values in the 3D subsurface of Bangalore, three geostatistical models (simple kriging, ordinary kriging and disjunctive kriging) have been developed. Simple and ordinary kriging produces linear estimator whereas, disjunctive kriging produces nonlinear estimator. The knowledge of the semivariogram of the Nc data is used in the kriging theory to estimate the values at points in the subsurface of Bangalore where field measurements are not available. The capability of disjunctive kriging to be a nonlinear estimator and an estimator of the conditional probability is explored. A cross validation (Q1 and Q2) analysis is also done for the developed simple, ordinary and disjunctive kriging model. The result indicates that the performance of the disjunctive kriging model is better than simple as well as ordinary kriging model. This study also describes two ANN modelling techniques applied to predict Nc data at any point in the 3D subsurface of Bangalore. The first technique uses four layered feed-forward backpropagation (BP) model to approximate the function, Nc=f(x, y, z) where x, y, z are the coordinates of the 3D subsurface of Bangalore. The second technique uses generalized regression neural network (GRNN) that is trained with suitable spread(s) to approximate the function, Nc=f(x, y, z). In this BP model, the transfer function used in first and second hidden layer is tansig and logsig respectively. The logsig transfer function is used in the output layer. The maximum epoch has been set to 30000. A Levenberg-Marquardt algorithm has been used for BP model. The performance of the models obtained using both techniques is assessed in terms of prediction accuracy. BP ANN model outperforms GRNN model and all kriging models. SVM model, which is firmly based on the theory of statistical learning theory, uses regression technique by introducing -insensitive loss function has been also adopted to predict Nc data at any point in 3D subsurface of Bangalore. The SVM implements the structural risk minimization principle (SRMP), which has been shown to be superior to the more traditional empirical risk minimization principle (ERMP) employed by many of the other modelling techniques. The present study also highlights the capability of SVM over the developed geostatistic models (simple kriging, ordinary kriging and disjunctive kriging) and ANN models. Further in this thesis, Liquefaction susceptibility is evaluated from SPT, CPT and Vs data using BP-ANN and SVM. Intelligent models (based on ANN and SVM) are developed for prediction of liquefaction susceptibility using SPT data from the 1999 Chi-Chi earthquake, Taiwan. Two models (MODEL I and MODEL II) are developed. The SPT data from the work of Hwang and Yang (2001) has been used for this purpose. In MODEL I, cyclic stress ratio (CSR) and corrected SPT values (N1)60 have been used for prediction of liquefaction susceptibility. In MODEL II, only peak ground acceleration (PGA) and (N1)60 have been used for prediction of liquefaction susceptibility. Further, the generalization capability of the MODEL II has been examined using different case histories available globally (global SPT data) from the work of Goh (1994). This study also examines the capabilities of ANN and SVM to predict the liquefaction susceptibility of soils from CPT data obtained from the 1999 Chi-Chi earthquake, Taiwan. For determination of liquefaction susceptibility, both ANN and SVM use the classification technique. The CPT data has been taken from the work of Ku et al.(2004). In MODEL I, cone tip resistance (qc) and CSR values have been used for prediction of liquefaction susceptibility (using both ANN and SVM). In MODEL II, only PGA and qc have been used for prediction of liquefaction susceptibility. Further, developed MODEL II has been also applied to different case histories available globally (global CPT data) from the work of Goh (1996). Intelligent models (ANN and SVM) have been also adopted for liquefaction susceptibility prediction based on shear wave velocity (Vs). The Vs data has been collected from the work of Andrus and Stokoe (1997). The same procedures (as in SPT and CPT) have been applied for Vs also. SVM outperforms ANN model for all three models based on SPT, CPT and Vs data. CPT method gives better result than SPT and Vs for both ANN and SVM models. For CPT and SPT, two input parameters {PGA and qc or (N1)60} are sufficient input parameters to determine the liquefaction susceptibility using SVM model. In this study, an attempt has also been made to evaluate geotechnical site characterization by carrying out in situ tests using different in situ techniques such as CPT, SPT and multi channel analysis of surface wave (MASW) techniques. For this purpose a typical site was selected wherein a man made homogeneous embankment and as well natural ground has been met. For this typical site, in situ tests (SPT, CPT and MASW) have been carried out in different ground conditions and the obtained test results are compared. Three CPT continuous test profiles, fifty-four SPT tests and nine MASW test profiles with depth have been carried out for the selected site covering both homogeneous embankment and natural ground. Relationships have been developed between Vs, (N1)60 and qc values for this specific site. From the limited test results, it was found that there is a good correlation between qc and Vs. Liquefaction susceptibility is evaluated using the in situ test data from (N1)60, qc and Vs using ANN and SVM models. It has been shown to compare well with “Idriss and Boulanger, 2004” approach based on SPT test data. SVM model has been also adopted to determine over consolidation ratio (OCR) based on piezocone data. Sensitivity analysis has been performed to investigate the relative importance of each of the input parameters. SVM model outperforms all the available methods for OCR prediction.
19

A Concept for the Investigation of Riverbank Filtration Sites for Potable Water Supply in India / Ein Konzept für die Untersuchung von Uferfiltrationsstandorten für die Trinkwasserversorgung in Indien

Sandhu, Cornelius Sukhinder Singh 31 August 2016 (has links) (PDF)
Die Uferfiltration (UF) ist eine potentielle Alternative zur konventionellen Oberflächenwasseraufbereitung in Indien, da Trübstoffe, pathogene Mikroorganismen und organische Wasserinhaltsstoffe effektiv entfernt werden. In dieser Arbeit wurde erstmals ein umfangreicher Überblick zu bestehenden UF-Anlagen in Indien erarbeitet. Für die Standorterkundung und -bewertung wurde ein Konzept erarbeitet, das an drei Standorten entlang des Ganges getestet und weiterentwickelt wurde. Das Konzept umfasst vier Stufen: Standortvorerkundung, Bestimmung von Grundwasserleiterparametern, Erfassung von hydraulischen und Beschaffenheits-parametern sowie numerische Grundwasser-strömungsmodellierung. Entlang des oberen Flusslaufes des Ganges (Haridwar und Srinagar) wurden günstige geohydraulische Verhältnisse identifiziert (kf = 10E-4 bis 10E-3 m/s, Grundwasser leitermächtigkeit 11 bis 20 m). Entlang des unteren Flusslaufes (Patna) gibt es in Abhängigkeit von der Mächtigkeit der Sedimentablagerungen im Ganges nur bei erhöhter Schleppkraft im Monsun eine gute hydraulische Verbindung zwischen dem Fluss und dem Grundwasserleiter. In Haridwar wurde der Uferfiltratanteil im Rohwasser mittels Isotopenanalysen (δ18O) und Leitfähigkeitsmessungen im Fluss- und Rohwasser ermittelt. Der Uferfiltratanteil in den auf einer Insel und südlich davon gelegenen Brunnen liegt bei bis zu 90%. An den untersuchten Standorten wird durch die UF eine effektive Entfernung von E. coli um 3,5 bis 4,4 Log10 und der Trübung bis >2 Log10 Einheiten erreicht. Eine Entfernung von 3 Log10 Einheiten wurde bereits bei einer Fließzeit des Uferfiltrats von zwei Tagen beobachtet. Die erhöhte Anzahl an Coliformen in einigen Brunnen am Standort Haridwar resultiert aus Verunreinigungen des landseitigen Grundwassers. Bei Hochwässern und Starkregenereignissen muss eine Kontamination durch den direkten Eintrag von Wasser durch undichte Brunnenabdeckungen, Risse in den Schächten bzw. unsachgemäßen Brunnenbau berücksichtigt werden. Die Anwendung des angepassten Untersuchungskonzepts an 15 weiteren UF-Standorten in Indien hat gezeigt, dass die niedrigen DOC-Konzentrationen im Flusswasser (0,9 bis 3,0 mg/L) und im Brunnenwasser (0,4 bis 2,3 mg/L) günstig für die Anwendung der UF sind. Bei erhöhten DOC-Konzentrationen (Vormonsun) im Flusswasser konnte in Delhi und Mathura im Monsun eine 50%ige Verminderung erreicht werden. Bei der Erkundung neuer UF-Standorte in bergigen Gebieten sind die Grundwasserleitermächtigkeit mit geophysikalischen Erkundungsverfahren, die Strömungsverhältnisse in den alluvialen Ablagerungen sowie lokale Hochwasserrisiken zu untersuchen. / Riverbank filtration or bank filtration (RBF / BF) is a potential alternative to the direct abstraction and conventional treatment of surface water by virtue of the effective removal of pathogens, turbidity, suspended particles and organic substances. A comprehensive overview of existing RBF systems in India has been compiled for the first time. To systematically select and investigate new and existing potential RBF sites in India, a methodological concept was developed and tested at three sites along the Ganga River. The four stages of the concept are: initial site-assessment, basic site-survey, monitoring of water quality and quantity parameters and determination of aquifer parameters and numerical groundwater flow modelling. Suitable geohydraulic conditions for RBF (hydraulic conductivity: 10E-4 to 10E-3 m/s, aquifer thickness: 11 to 20 m) exist along the upper course of the Ganga (Haridwar and Srinagar). Due to the presence of fine sediment layers beneath the river bed along the Ganga’s lower course (Patna), river-aquifer interaction occurs during increased shear stress on the riverbed in monsoon. The portion of bank filtrate abstracted by the wells in Haridwar was determined from isotope analyses (Oxygen 18) and electrical conductivity measurements of river and well water and is up to 90% for wells located on an island and between the river and a canal. The results were confirmed by groundwater flow modelling. A high removal of E. coli (3.5 to 4.4 Log10 units) and turbidity (>2 Log10 units) was observed at the investigated sites. An E. coli removal of 3 Log10 units was observed for short travel times of 2 days. Higher coliform counts in some wells occur due to contamination from landside groundwater. During floods and intense rainfall events, contamination of RBF wells from direct entry of flood water, seepage of surface runoff into the well through leaky covers, fissures in the well-heads / caissons and in-appropriately sealed well-bases has to be considered. The application of the adapted investigation concept to 15 other sites in India showed that the low DOC concentrations in river water (0.9 to 3.0 mg/L) and well-water (0.4 to 2.3 mg/L) are favourable for the application of RBF. A 50% decrease of the high (pre-monsoon) DOC concentration was observed during monsoon in Delhi and Mathura. For the exploration of new RBF sites in hilly / mountainous areas, investigations of the aquifer thickness using geophysical methods, subsurface flow conditions in the alluvial deposits and the risk from floods should be conducted.
20

Performance of penetrometers in deepwater soft soil characterisation

Low, Han Eng January 2009 (has links)
Offshore developments for hydrocarbon resources have now progressed to water depths approaching 2500 m. Due to the difficulties and high cost in recovering high quality samples from deepwater site, there is increasing reliance on in situ tests such as piezocone and full-flow (i.e. T-bar and ball) penetration tests for determining the geotechnical design parameters. This research was undertaken in collaboration with the Norwegian Geotechnical Institute (NGI), as part of a joint industry project, to improve the reliability of in situ tests in determining design parameters and to improve offshore site investigation practice in deepwater soft sediments. In this research, a worldwide high quality database was assembled and used to correlate intact and remoulded shear strengths (measured from laboratory and vane shear tests) with penetration resistances measured by piezocone, T-bar and ball penetrometers. The overall statistics showed similar and low levels of variability of resistance factors for intact shear strength (N-factors) for all three types of penetrometer. In the correlation between the remoulded penetration resistance and remoulded shear strength, the resistance factors for remoulded shear strength (Nrem-factors) were found higher than the N-factors. As a result, the resistance sensitivity is less than the strength sensitivity. The correlations between the derived N-factors and specific soil characteristics indicated that the piezocone N-factors are more influenced by rigidity index than those for the T-bar and ball penetrometers. The effect of strength anisotropy is only apparent in respect of N-factors for the T-bar and ball penetrometers correlated to shear strengths measured in triaxial compression. On the other hand, the Nrem-factors showed slight tendency to increase with increasing strength sensitivity but were insensitive to soil index properties. These findings suggest that the full-flow penetrometers may be used to estimate remoulded shear strength and are potentially prove more reliable than the piezocone in estimating average or vane shear strength for intact soil but the reverse is probably true for the estimation of triaxial compression strength.

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