Interação de interfaces entre solo e geomembranas por meio de ensaios de cisalhamento direto

Abstract

The present research aims to study the interaction of waterproofing systems’ interfaces of landfills, formed by a fine soil and geomembranes textured and smooth. The soil was collected in deformed samples from a deposit in the municipality of Minas do Leão, Rio Grande do Sul. The physical and mechanical characterization were realized by laboratorial tests, focusing on the shear behavior of the material. Fifty-eight interface’s shear resistance tests were realized, varying the composition created between soil and geomembrane and scale of the test. The deposit was classified as clay, presenting lateritic behavior. The geomembranes were utilized in the research in their virgin and damaged conditions. The damage considered geomembranes exhumed from a landfill and damaged produced by procedures, aiming to compare the evolution of shear resistance’s results due to the aging by temperature, leachate action and ultraviolets rays. The soil was classified according to shear resistance using five normal tensions, being: 25, 50, 100, 200 e 400 kPa, and presented strain hardening behavior. In relation to the direct shear tests, the interfaces were evaluated according to the insertion of texture, damage and scale. The insertion of geosynthetic materials reduces the soil’s particles interlocking, decreasing the shear resistance in relation to the soil-soil interface, as so reaching the lower result for soil-smooth geomembrane interface. Regarding the damage, the shear resistance was altered due to the insertion of friction at the surface of the geosynthetic material, caused by the damage, creating a better interaction between layers. Finally, the interfaces evaluated in large-scale direct shear reached more conservative shear resistance values compared to conventional tests.