Validação de modelos simplificados de previsão do tempo de liquefação através de ensaios de centrifugadora
DOI:
https://doi.org/10.24849/j.geot.2020.148.03Palavras-chave:
liquefação, ensaios de centrifugadora, métodos simplificados, métodos baseados na energia.Resumo
Os danos resultantes da ocorrência de sismos podem resultar da combinação da excitação sísmica e/ou de incrementos de pressão neutra no solo (liquefação). Estes dois efeitos estão interligados, uma vez que a redução da rigidez do solo por efeito da diminuição da tensão efetiva altera o comportamento mecânico do solo, nomeadamente a sua resposta sísmica. Assim, o nível e o tipo de danos são dependentes da velocidade de aumento da pressão neutra e do tempo para o qual a liquefação é desencadeada no solo, associada à energia sísmica libertada ao longo do tempo. No entanto, a maioria dos métodos simplificados de previsão da liquefação foca-se na identificação desse desencadeamento e não no tempo para o qual esta se desenvolve. Assim, é fundamental melhorar e desenvolver estes métodos para que possam fornecer estimativas confiáveis do efeito deste processo de aumento de pressão neutra e consequente progresso da liquefação nos horizontes sensíveis. Nesse sentido, os ensaios de centrifugadora são uma excelente oportunidade para validar esses métodos. Este artigo apresenta dois métodos simplificados de previsão da liquefação, e valida-os através da sua utilização para prever o aumento da pressão neutra numa série de ensaios de centrifugadora.
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