Avaliação de novas texturas para otimização da resistência ao cisalhamento de interface em geomembranas

Abstract

Geosynthetics are extremely versatile materials and they are applicable in civil engineering, with geomembranes, one of the most used types, considering, especially, its use in geoenvironmental engineering works. The main function of geomembranes is to act as a barrier against the flow of gases and liquids, being applicable in projects like water and waste containment ponds, landfills, dams, and other earthworks. However, the interface between the geomembrane and the soil is a critical factor that must be analyzed, because this interaction can be susceptible to localized safety problems and even the total collapse of the structure. In this work, different types of geomembranes in contact with a sand will be analyzed, and the analysis criterion used will be the interface shear strength, an important factor for verifying the safety of geotechnical structure that include geosynthetics. The texture and roughness of geomembrane are essential factors for the interface shear resistance, because the mechanical adhesion and interlocking mobilized in the contact zone increase adhesion and friction angle, which are fundamental factors for the increase of this resistance. The present work aims to analyze different types of geomembranes in interaction with a sand and to propose new textures of geomembranes, suitable to ensure an improvement in the interface shear strength parameters. To achieve this work, direct shear tests will be conducted on four existing types of geomembranes: one smooth and three textured. In addition, characterization of geomembranes will be carried out using scanning electron microscopy, using the enlargement of the geomembrane images, with the aim to evaluate the surface of the materials. With the results of these analyses, new models of geomembrane will be proposed, which will be modeled in digital files and printed using 3D printers. It is concluded that the printed geomembranes exhibited peak shear strength values very similar to those of commercial geomembranes. However, they showed superior residual shear strength performance, especially under lower normal stresses, demonstrating a potential for the use of these new geomembranes, especially the GI12, mainly for covering sanitary landfills and waterproofing channels.