Determinação da curva característica solo-água de um solo laterítico do oeste do Paraná pelo método do papel-filtro

Abstract

The study of unsaturated soils is essential for understanding their hydraulic and mechanical behavior, with the Soil-Water Characteristic Curve (SWCC) being one of the main parameters used in this analysis. This study aimed to determine the SWCC of a lateritic clay soil from the region of Quatro Pontes/PR using the filter paper method, an indirect technique that relates soil moisture to matric suction. The research is justified by the need for local data to analyze the stability of road slopes exposed to moisture variations throughout the year. The methodology involved the use of undisturbed samples, their physical characterization, and the application of the filter paper method to obtain SWCC data points. The data were fitted using the Gitirana and Fredlund (2004) model, resulting in high accuracy (R² 0.999) and highlighting the bimodal behavior of the soil, typical of lateritic materials, with two distinct air-entry values (b), namely b₁ = 3.0 kPa and b₂ = 3500.0 kPa, associated with the presence of micropores and macropores, respectively. The method proved effective, corroborating previous studies on similar soils. It is concluded that the filter paper technique is a viable alternative for obtaining the SWCC, providing consistent data for geotechnical engineering and contributing to the understanding of water retention dynamics in unsaturated soils.