Thesis (M. Sc.)--University of Hong Kong, 2005.

Orientador: Paulina Setti Riedel / Banca: Maria José Brollo / Banca: Iandara Alves Mendes / Resumo: As características geotécnicas do solo, na maioria dos casos, não são consideradas nas intervenções feitas na estrutura urbana, pôr conseguinte também não as são nas expansões urbanas. Como conseqüência disso, verificam-se freqüentemente problemas como movimentos de massa, inundações, assoreamento de rios e igarapés, e erosões. O mapeamento geotécnico surge então como uma ferramenta indispensável para auxiliar o planejamento das intervenções necessárias para acompanhar o rápido crescimento urbano. Na obtenção do zoneamento geotécnico de uso geral, através da utilização do Sensoriamento Remoto, de nossa área de estudo-Sítio urbano do Município de Rio Branco/Ac e seus arredores, foram desenvolvidas três etapas. A primeira etapa consistiu na realização da compartimentação fisiográfica da área com base na análise de elementos texturais de relevo e drenagem e de suas estruturas em imagens fotográficas, obtendo-se assim as unidades básicas de compartimentação (UBC's). Na segunda etapa, estas unidades foram caracterizadas em função de cinco fatores geotécnicos (alterabilidade, permeabilidade, declividade, tipo do material do manto de alteração e espessura do manto de alteração) considerados básicos para subsidiar a avaliação das unidades quanto ao seu potencial de uso. Na terceira etapa as unidades básicas de compartimentação são classificadas quanto ao grau relativo de aptidões /restrições para fins de expansão urbana. / Abstract: Geotechnical characteristics of the soil are rarely taken into consideration when interventions are made in the urban structure, nor, consequently, in urban expansions. As a consequence, there are often problems with landslides, floods, silt accumulation in rivers and sand bars and erosion. Geotechnical mapping has emerged as an indispensable tool to help plan the interventions needed to keep up with rapid urban growth. In this study, three stages were developed to obtain geotechnical zoning for general use in the study area, urban area of the Municipality of Rio Branco, in the state of Acre, using remote sensing. The first stage involved carrying out physiographic subdivision of the area based on analysis of textural elements of the relief and drainage system, and of their structures in photographic images, thus obtaining basic units of sub-division . In the second stage, these units were characterized according to five geotechnical factors (alterability, permeability, slope, type of material of the mantle of alteration, and thickness of the mantle of alteration) considered to be basic for the evaluation of the units with respect to their potential use. In the third stage, the basic units of sub-division were classified according to their relative degree of suitability/restrictions for urban expansion. / Mestre

Made available in DSpace on 2014-06-11T19:32:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-06Bitstream added on 2014-06-13T20:03:41Z : No. of bitstreams: 1 oliveira_ffg_dr_rcla.pdf: 4610872 bytes, checksum: 45e52968a1567896d83779b200a2257f (MD5) / Este trabalho objetiva identificar analiticamente os impactos ambientais negativos e determinar, a partir de modelos empíricos, em escala de 1:25.000, os graus de vulnerabilidade ambiental existentes no litoral sul do Estado do Rio Grande do Norte. Os resultados dos impactos foram obtidos mediante a proposição de metodologias de geoprocessamento específicas para cada impacto. A distribuição das diferentes classes de vulnerabilidade ambiental foi determinada a partir de modelamentos por álgebra de mapas. Os impactos ambientais analisados configuram-se nos campos de dunas, manguezais, faixas de praia e remanescentes florestais de Mata Atlântica. Quanto às dunas, o mapeamento indicou que 48,24% da área têm uma magnitude de impacto classificada como muito fraca. Contudo, o que preocupa é que os locais onde a magnitude do impacto é muito forte são exatamente as áreas com maior vulnerabilidade ambiental. Atualmente o maior avanço da carcinicultura ocorre em áreas que não são de manguezais, mas em sistemas ambientais associados. As faixas de praia podem se diferenciar quanto ao seu comprometimento ambiental, pois a capacidade de suporte aos impactos desses ambientes varia em função de suas características geoambientais. Apesar de os fragmentos florestais de Mata Atlântica apresentarem predominância de áreas muito irregulares (60,39%), muito pequenas (64,08%), com proporção de borda de 54,34%, má distribuição de sua densidade (setor sul) e circundados por cana-de-açúcar e áreas campestres (72,04%), eles ainda são responsáveis pelo controle geossistêmico e ecológico da área. Quanto à vulnerabilidade ambiental, verificou-se de que mais de 80% da área é classificada como de baixa e moderada vulnerabilidade. Isso mostra que, de acordo com o método aplicado e com os... / This study aims to identify analytically the negative environmental impacts and determine, based on empirical models, on a scale of 1:25,000, the existing degree of environmental vulnerability in the south coast of Rio Grande do Norte. The results of the impacts were obtained by the proposition of geoprocessing methodologies specific to each impact. The distribution of different classes of environmental vulnerability were determined from models for map algebra. The environmental impacts analyzed, are configured in the fields of dunes, mangroves, beach strips and areas of Mata Atlantica. Refering to the dunes, the mapping indicated that 48.24% of the area has a magnitude of impact rated as very small. However, the problem is that the locations where the magnitude of impact is very strong are the areas with greater environmental vulnerability. Currently the largest improvement in shrimp farming occurs in areas that are not mangrove, but in associated environmental systems.The beach strips may differ as to its environmental commitment, because the ability to support the impacts of these environments varies with geo-environmental characteristics. Although the present Mata Atlantica forest fragments shows predominance of very irregular areas (60.39%), very small (64.08%), with proportion of edge of 54.34%, bad distribution of density (southern sector) and surrounded by sugar cane fields and grassland (72.04%), they are still responsible for controlling geosystems and ecological area. Refering to the environmental vulnerability, we have concluded that more than 80% of the area is classified as low-and moderate vulnerability. This shows that, according to the method used and results achieved, most of the area is in balance. However... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:32:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-11-08Bitstream added on 2014-06-13T19:47:12Z : No. of bitstreams: 1 nogueira_fr_dr_rcla.pdf: 6690879 bytes, checksum: d442517932963e0eff714639dec3f0ee (MD5) / O objetivo desta pesquisa foi a construção de um modelo conceitual e operacional para o gerenciamento municipal de riscos ambientais associados a escorregamentos em áreas de ocupação subnormal. Para tanto, foram adotadas duas vertentes metodológicas: (1) a revisão crítica de ampla bibliografia temática compilada, tendo como parâmetro a aplicabilidade à gestão municipal brasileira; e (2) à luz da teoria, a avaliação dos acertos e das dificuldades da prática pública de gerenciamento de riscos associados a escorregamentos nos municípios visitados ou acompanhados pelo pesquisador. Apresentam-se, ao longo do texto, conceitos e instrumentos operacionais úteis para técnicos e gestores públicos. No capítulo 6, os resultados da pesquisa estão sintetizados na forma de diretrizes e de um modelo para o gerenciamento de riscos ambientais associados a escorregamentos em áreas ocupadas por favelas e loteamentos irregulares, aplicáveis às diferentes realidades ambientais e urbanas do país. / The goal of this research was the construction of a conceptual and operative model for the local management of environmental risks associated with landslides in areas of subnormal urbanization. To achieve this goal, two methodological perspectives were adopted: (1) a critical revision of the broad thematic bibliography assembled, having its application to the Brazilian municipal management as a framework; (2) the use of theoretical approaches to evaluate accomplishments and difficulties experienced by public managers of landslide risks in some Brazilian cities. Throughout the paper, concepts and operative tools for technicians and public sector managers are presented. The chapter 6th. presents the synthesis of the products organized as directives and a model for management for environmental risks associated to landslides in sites occupied by slums and illegal settlements. These models are meant to be applicable to diverse environmental and urban realities of the country.

Orientador: Kenitiro Suguio / Banca: Omar Yazbek Bitar / Banca: Celso Santos Carvalho / Banca: Flavio Farah / Banca: Leandro Eugenio da Silva Cerri / Resumo: O objetivo desta pesquisa foi a construção de um modelo conceitual e operacional para o gerenciamento municipal de riscos ambientais associados a escorregamentos em áreas de ocupação subnormal. Para tanto, foram adotadas duas vertentes metodológicas: (1) a revisão crítica de ampla bibliografia temática compilada, tendo como parâmetro a aplicabilidade à gestão municipal brasileira; e (2) à luz da teoria, a avaliação dos acertos e das dificuldades da prática pública de gerenciamento de riscos associados a escorregamentos nos municípios visitados ou acompanhados pelo pesquisador. Apresentam-se, ao longo do texto, conceitos e instrumentos operacionais úteis para técnicos e gestores públicos. No capítulo 6, os resultados da pesquisa estão sintetizados na forma de diretrizes e de um modelo para o gerenciamento de riscos ambientais associados a escorregamentos em áreas ocupadas por favelas e loteamentos irregulares, aplicáveis às diferentes realidades ambientais e urbanas do país. / Abstract: The goal of this research was the construction of a conceptual and operative model for the local management of environmental risks associated with landslides in areas of subnormal urbanization. To achieve this goal, two methodological perspectives were adopted: (1) a critical revision of the broad thematic bibliography assembled, having its application to the Brazilian municipal management as a framework; (2) the use of theoretical approaches to evaluate accomplishments and difficulties experienced by public managers of landslide risks in some Brazilian cities. Throughout the paper, concepts and operative tools for technicians and public sector managers are presented. The chapter 6th. presents the synthesis of the products organized as directives and a model for management for environmental risks associated to landslides in sites occupied by slums and illegal settlements. These models are meant to be applicable to diverse environmental and urban realities of the country. / Doutor

No description available.

published_or_final_version / Applied Geosciences / Master / Master of Science

The purpose of this study is to improve site investigation in geotechnical engineering via the evaluation and development of statistical approaches for characterizing the spatial variability of soil properties and the development of site investigation simulation software for educational use. This study consists of four components: statistical characteristics, data measurement, simulation, and educational training. Statistical measures of spatial variability of soil properties were examined for three different geographical areas where soil formation processes differ to assess the influence on the spatial variability of soils. Statistical measures of spatial variability were also calculated for a case history where blasting was used as a method of soil improvement to evaluate the effects of man-made changes to soil structure. The concept of spatial aliasing was employed to estimate the maximum allowable sampling interval for field data as a function of the spatial correlation properties. Once a maximum statistically allowable sampling interval is determined for a specific soil property, the minimum statistically required number of soundings / borings is calculated to perform an economical site investigation at a specific site. A simple and efficient simulation technique was proposed to generate correlated, multi-dimensional simulations of soil properties. Based on limited data, the proposed simulation technique generated accurate and correlated simulations of soil properties that are consistent with the observed or proposed correlation structures of soil properties. Lastly, a geotechnical site investigation simulation program with a wide variety of in situ and laboratory tests was developed to allow students to plan and perform a comprehensive site investigation program. The simulation generates an input file based partly on the statistical characteristics of the spatial variability of soil properties analyzed in this study and partly on traditional values. Spatial variability in soil properties is modeled via correlated random fields, interpolation, and a decomposition method to yield realistic geotechnical data. Via the simulation, students are able to obtain experience and judgment in an essential component of geotechnical engineering practice. The four components of this research (statistical characteristics, data measurement, simulation, and educational training) focus on the improvement of site investigation performance in geotechnical engineering, thereby improving reliability analysis in geotechnical practice.

Photocopy of typescript. / Digitized by Kansas State University Libraries

The phenomenon known as the ‘arching effect’ occurs when a portion of granular mass yields relative to an adjacent stationary region. The movement is resisted by shearing stresses which act to reduce the pressure on the yielding support and increase the pressure on the adjacent stationary supporting zones. Arching is widely observed in both natural and man-made structures such as piled embankments, tunnelling, and above mine works and sinkholes. In this research the arching effect is recreated in the increased gravity environment of a geotechnical centrifuge where the pressure distribution across both the yielding and supporting soil masses is measured and the resulting soil displacements observed. A motor driven ‘trapdoor’ apparatus was built inside a plane strain container to model the yielding support. Both the trapdoor and an adjacent support were instrumented to measure the force (and derived pressure) distribution. Soil and trapdoor displacements are determined by analysis of digital images taken in-flight through a Perspex wall of the container. One method of increasing soil shear strength and its resistance to deformation is the reinforcement of soil with randomly distributed discrete fibres. The degree of improvement has been shown to be directly related to the fibre content in the soil, the fibre aspect ratio, orientation and mechanical properties. In this research the effect of fibre reinforcement on the arching process and resulting deformation is examined by variation of fibre parameters such as fibre aspect ratio and volumetric content of fibre. The influence of fibre and model scale effects were investigated by conducting a modelling of models exercise whereby trapdoor scale and effective stress were varied whilst maintaining a constant cover depth to structure width ratio, and compaction effort. The results were compared directly with those obtained for unreinforced soil trapdoor tests in order to determine the extent of improvement offered by fibre-reinforcement.