Ajuste da curva de retenção de água do solo da camada de cobertura de uma célula experimental de resíduos sólidos urbanos.

Abstract

Landfills require constant monitoring of their cover layer in order to improve their ability to isolate Urban Solid Waste (MSW) and to avoid exposure of these wastes to the environment. Sanitary landfills generally have a layer of waterproofing cover that restricts the contact of these residues with the external environment, in addition to preventing gases generated inside the cell from coming into contact with the environment and that the rainwater falls to the inside Cell. The determination of the most suitable soil to compose the cover layer is of paramount importance for the study of the sanitary landfills, considering the need to isolate the wastes that make up the landfill. The present work consists in the analysis of the cover layer of an experimental cell, which simulates a landfill cell, located at the Federal University of Campina Grande, Paraíba, to evaluate the suction / moisture ratio of the soil and to compare it with the layer landfill coverage. Undeformed samples were taken from the compacted soil cover layer of the experimental cell and taken to the Environmental Geotechnics laboratory where the suction measurement was carried out by the filter paper method, enabling the data required to construct the soil water retention curve. Using the STATISTICA for Windows 8.0 software, it was possible to adjust the curve to obtain the necessary parameters, such as the Determination Coefficient (R²), Sum of Squares of Residuals (SQR) and the AKAIKE Information Criterion (AIC). model that best suits the studied soil. The results showed that the soil water retention curve of the cover layer of the experimental cell presented low retention of water, characterizing a sandy soil, unlike the previous characterization, that found a classification for a clay soil, demonstrating that the soil studied underwent alterations with time due to weathering, leaching, temperature variations, allowing nonconformity with the suction / moisture ratio of a clay soil. From the adjusted curve, it was verified that the Van Genuchten equation better represented the studied soil due to the statistical parameters found. It was also possible to determine, from the soil water retention curve analysis, that the soil of the landfill cover layer was more effective for the cover layer purpose, considering its greater water retention capacity in comparison with the soil of the cover layer of the experimental cell.