Análise do comportamento de um solo arenoso não saturado afetado por um processo erosivo hídrico
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Data
2018-09-05
Autores
Barros, Amanda Leoncini Carvalho
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Países com clima tropical sofrem frequentemente com o fenômeno da erosão. Devido às condições climáticas, que variam entre longos períodos de seca e chuvas intensas, em conjunto com a ação antrópica, este fenômeno tem seu efeito acelerado e pode causar graves consequências para o meio ambiente. Apesar do grande número de trabalhos publicados sobre o fenômeno erosivo, pouco deles aborda esse assunto sobre uma perspectiva da Mecânica dos Solos Não Saturados, muito comum nas regiões de clima tropical. Esta dissertação apresenta uma caracterização hidromecânica de um solo não saturado coletado de uma microbacia da cidade de Bauru-SP afetada por um processo erosivo hídrico e, conjuntamente, avalia o mecanismo de erodibilidade ocorrido na área. Os parâmetros hidráulicos foram obtidos pelos de retenção da água no solo e permeabilidade. Os parâmetros mecânicos foram obtidos pelos ensaios de compressão triaxial e edométricos, ambos com sucção controlada. Os resultados desses ensaios mostraram a influência da sucção tanto nos parâmetros de resistência ao cisalhamento do solo quanto nos de compressibilidade. A avaliação do mecanismo de erodibilidade foi realizada com base nos resultados encontrados nos ensaios de compressão triaxial e Inderbitzen, sendo esse último disponível no histórico de informações da microbacia. Essa avaliação constatou que o aumento da sucção pode contribuir contra o efeito da erosão uma vez que interfere na sua resistência através do intercepto de coesão. Entretanto, caso haja uma chuva intensa na área, essa contribuição pode durar poucos minutos, pois a microbacia não possui um sistema de drenagem eficiente e a camada superficial se saturada rapidamente e, consequentemente, perde o intercepto de coesão que estava disponível antes da chuva. O trabalho realizado evidencia um severo processo erosivo na microbacia Água Comprida e ainda permite um avanço nos estudos desse solo em termos do conceito da Mecânica dos Solos Não Saturados.
Countries with tropical climate often suffer from the erosion phenomenon. Due to the climatic conditions, which vary between long periods of drought and intense rains, together with the anthropic action, this phenomenon has its effect accelerated and can cause serious consequences for the environment. In spite of the great number of published works on the erosive phenomenon, few of them approach this subject on a perspective of the Mechanics of Unsaturated Soils, very common in the regions of tropical climate. This dissertation presents a hydromechanical characterization of an unsaturated soil collected from a microbasin of Bauru-SP city affected by an erosive water process and, together, evaluates the mechanism of erodibility occurred in the area. The hydraulic parameters were obtained by the soil-water retention and permeability. The mechanical parameters were obtained by triaxial and edometric compression tests, both with controlled suction. The results of these tests showed the influence of suction on both the shear strength and the compressibility parameters. The evaluation of the erodibility mechanism was carried out based on the results found in the triaxial and Inderbitzen tests, the latter being available in the history of the microbasin information. This evaluation found that increased suction may contribute to the erosion effect since it interferes with its resistance through the cohesion parameter. However, if there is heavy rainfall in the area, this contribution may last for a few minutes because the microbasin does not have an efficient drainage system and the surface layer is rapidly saturated and consequently loses the cohesion intercept that was available before the rain. The work carried out evidences a severe erosive process in the Água Comprida microbasin and still allows an advance in the studies of this soil in terms of the concept of the Mechanics of Unsaturated Soils.
Countries with tropical climate often suffer from the erosion phenomenon. Due to the climatic conditions, which vary between long periods of drought and intense rains, together with the anthropic action, this phenomenon has its effect accelerated and can cause serious consequences for the environment. In spite of the great number of published works on the erosive phenomenon, few of them approach this subject on a perspective of the Mechanics of Unsaturated Soils, very common in the regions of tropical climate. This dissertation presents a hydromechanical characterization of an unsaturated soil collected from a microbasin of Bauru-SP city affected by an erosive water process and, together, evaluates the mechanism of erodibility occurred in the area. The hydraulic parameters were obtained by the soil-water retention and permeability. The mechanical parameters were obtained by triaxial and edometric compression tests, both with controlled suction. The results of these tests showed the influence of suction on both the shear strength and the compressibility parameters. The evaluation of the erodibility mechanism was carried out based on the results found in the triaxial and Inderbitzen tests, the latter being available in the history of the microbasin information. This evaluation found that increased suction may contribute to the erosion effect since it interferes with its resistance through the cohesion parameter. However, if there is heavy rainfall in the area, this contribution may last for a few minutes because the microbasin does not have an efficient drainage system and the surface layer is rapidly saturated and consequently loses the cohesion intercept that was available before the rain. The work carried out evidences a severe erosive process in the Água Comprida microbasin and still allows an advance in the studies of this soil in terms of the concept of the Mechanics of Unsaturated Soils.
Descrição
Palavras-chave
Erosão, Ensaio com controle de sucção, Inderbitzen., Solo não saturado, Erosion, Unsaturated soil, Suction control test