Terras caídas: caracterização e modelagem geotécnica do fenômeno erosivo amazônico

Abstract

The main objective of this research is the characterization and geotechnical modeling of embankments in river banks in the state of Amazonas, affected by the remarkable phenomenon of fallen lands. To accomplish this, we will use a vast theory developed in Soil Mechanics to fully characterize the identification of the soils that make up the affected massifs and, posteriori, knowledge of the permeability of the layers, geostatic stresses to which the masses are subjected, the resistance to shear and finally the slope stability in miniature models (recreation of the phenomenon in scale). The field of study will be a locality close to the city of Manaus (approximately 7km), where the phenomenon has developed in a gradual and interesting way to the research. At the end of this research, with the aid of satellite images, it was observed that the phenomenon is in full development, modifying with each new cycle of flood/ebb the landscape. By means of the physical, chemical and mechanical characterization tests, the layers of soils studied are classified as silty and sandy soils with a low amount of clay, which is very active. In terms of resistance, either to compression or to shear, the base soils have low bearing capacity, unlike intermediate and top soils. Through the computational modeling, it was recorded that besides the variables of chemical and mineral composition, the arrangement, permeability and ability to resist cutting, the fluvial regime (flood/ebb) is a determining factor for the balance of slopes bordering rivers of muddy water.