26 resultados para Slope Landslides
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Pós-graduação em Geociências e Meio Ambiente - IGCE
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A ocorrência de escorregamentos translacionais no litoral paulista é parte integrante da evolução natural das encostas, que se intensifica sob condições de clima tropical em uma morfologia de serras com desníveis em torno de 700m. Sob precipitações intensas, mesmo sem a interferência direta do homem, os movimentos de massa ocorrem de forma isolada ou generalizada, como a centena de escorregamentos registrados no evento de janeiro de 1985, em que os índices pluviométricos atingiram 210 mm em 24 h. Utilizando um inventário de cicatrizes de escorregamentos obtido de um aerolevantamento de agosto de 1985, definiu-se como objetivo calibrar e validar um mapa de índice de estabilidade utilizando o modelo de análise de estabilidade de encostas por talude infinito, disponível no programa SINMAP, na Serra de Cubatão, na escala 1:10.000. O modelo foi aplicado considerando os parâmetros do solo constantes para toda área e também variáveis em função das unidades litológicas. Os resultados mostraram que mais de 79% das cicatrizes ficaram dentro dos limites inferior de estabilidade e superior de instabilidade para o caso de parâmetros constantes e mais de 95% das cicatrizes para o caso de parâmetros variáveis dentro dos mesmos limites. Palavras-chave: Índice de estabilidade, movimentos de massa, Serra do Mar.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This paper presents a study case in which a geosynthetic-reinforced soil (GRS) structure was used to rebuild a 12 m high slope after its failure. The failed slope is located between the parking lot of a private company and a public school. Due to surrounding structures restrictions, this project required a solution with rapidity in execution. In addition, as a requirement established by its owner, this structure should recover the original geometry of the slope. Besides the importance regarding surrounding constructions, an interesting aspect of this study case relies on the versatility of geosynthetic materials. A woven geotextile was used as reinforcement. Five other geosynthetic materials were used in this study case. Facing comprised a geocell filled with local soil cover and grass mats, resulting in a green facing. A geonet was used to hold the grass mats in place before grass roots development. Regarding the drainage system, geocomposite drains and geopipes were installed to drain subsurface water. A nonwoven geotextile was used as filter in drainage trenches, which were placed near the structure toe. Additionally to the GRS structure, the lower portion of the slope was reinforced with soil nailing technique. The face of the nailed soil portion was covered with sandbags and shotcrete. It emphasizes the flexibility of GRS structures regarding their application with other technical options in Geotechnical Engineering. The economic aspect of this study case also deserves attention. It did not require soil transportation and other design and construction steps, e.g. concrete structures design and construction.
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The disordered occupation in several cities in Brazil, is very common, especially during the rainy season, there are numerous cases of gravitational mass movements, with deads of human and builds destruction. The main objective of this work was to identify and map areas to mass movements, through the geo, the municipality of Várzea Paulista, the state of Sao Paulo. For the purpose, were prepared thematic maps of slope, geology, pedology, geomorphology and land use and occupation, which were overlaid using ArcGIS GIS Multicriteria Analysis. Each subject received a weight of influence to the outbreak of such processes and the final result was obtained map of susceptibility to mass movements of the city of Várzea Paulista. This survey found that there are many occupied areas within the city that require monitoring of the Government, especially in the rainy months, because they are in very fragile in terms of geological and geomorphological features. Considering that the data on the physical and natural aspects are scarce in the literature for this region, the results obtained in this study as well as the gathering of information of the physical and cartographic products developed, will greatly contribute to the administration of the municipality, subsidies they provide for the proper use planning and land tenure, pointing out the weak areas of the city geotechnical point of view
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The analysis of natural processes, such as landslides, has a great importance for the prevention of accidents in pipelines, since it might compromise its security, with serious social and environmental implications. Considering the large territorial dimensions that pipelines can reach, remote sensing tools have great applicability for data acquisition, allowing the analysis of large areas in regular time periods. This study aims to analyze the relations between the occurrence of landslides and its natural conditionings, on a stretch of the ORBEL pipeline, in the municipalities of Duque de Caxias, Nova Iguaçu and Belford Roxo – Rio de Janeiro. GeoEye sensor system images were used with spatial resolution of 0.5 m, from November/2009, January/2010 and March/2010, that are months of summer rains. The work involved the characterization of the study area and existing landslides, through bibliographic data collection; the application of visual analysis techniques for the extraction of landslide scars and fractures; preparation of maps for the landslide constraints and preparation of the susceptibility map. In the images from November only three landslide scars were extracted, while in January there were 166 and 111 in March. Difficulties were found with the shading in the images. From the relations among landslide scars, lithological units, relief systems, slope, downhill profile and the generated map of landslide susceptibility, presented in 1:70,000 scale, it was possible to conclude that slope is the main determinant of the process, allied secondarily to downhill profile, relief systems and lithology
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The understanding of the geo-morphological characteristics allows the identification of flood areas and instability slopes among others important features for land use planning. The study of the hydrological net and the analysis of morphometric parameters help in the geomorphologic characterization, providing specific physics indicators that quantify the risks for environmental damages. The present work used Geographic Information Systems (GIS) and carried out the morphometric analysis of two watersheds in the Alto Rio Sorocaba, municipality of Ibiuna (SP). Using digitalized topographic bases in the scale 1:50,000, the main morphometric parameters were extracted and the Digital Elevation Model (DEM) was obtained. Hence the slope, ground illumination, hill orientation and relief feature maps were elaborated. The characteristics for the two watersheds were quite similar, both have low risks for floods and landslides. Therefore, the concave feature is the predominant hill shape for both watersheds. The morphometric parameters directly related to the river density of the watersheds showed some differences, because the Sorocabuçú watershed presents higher value, resulting in a higher level of relief development. Thus, with this characterization it is possible to provide subsidies for environmental planning actions to the area.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)