Ensaio de piezocone em fluxo transitório: Modelagem poroelástica

velocidade utilizada para a cravação do cone é padronizada a 20 mm/s. Dessa forma, solos predominantemente arenosos tendem a apresentem comportamento drenado, sendo possível a análise baseada em tensões efetivas; e solos predominantemente argilosos tendem a apresentar comportamento não drenado, sendo possível a análise baseada em tensões totais. Contudo, para misturas ou solos siltosos a drenagem pode ser parcial. Nessa condição, a poropressão nas paredes do cone fica alterada e impossibilita a obtenção dos parâmetros do solo de forma confiável. O presente trabalho visa identificar o comportamento de drenagem de solos submetidos ao CPTu com características intermediárias de permeabilidade. Para avaliar o comportamento de drenagem durante a execução do ensaio, foram desenvolvidos ABSTRACT: CPTu (cone penetration tests with pore pressure measurements) is a test widely used to obtain geotechnical properties and stratigraphic characterization of the soil. In general, the speed used in the test is 20 mm / s. When assuming this speed, predominantly sandy soils tend to show drained behavior, the analysis is then based on effective tensions; and predominantly clay soils tend to show undrained behavior, in this case, the analyze is based on total stresses. However, for mixtures or silty soils, drainage may be partial. In this condition, the pore pressure on the cone is altered and obtaining soil parameters is not reliable. The present work aims to identify the drainage behavior of intermediate permeability soils submitted to CPTu. To evaluate the drainage behavior during the execution of the test, simplified semi-analytical models of cylindrical cavity expansion were developed. These models are based on the theories of poromechanics presented by Biot (1941). The Drucker-Praguer criterion was adopted using a non-linear shear module. From the developed models, parametric analysis was performed in relation to hydraulic conductivity. The generated curves were compared with field data from gold tailings deposits. The focus of parametric analysis is on drainage behavior. Theoretical drainage curves were characterized. Thus it is possible to relate the speed of expansion with the degree of drainage.