Geotechnical Behavior of Collapsible Soils in Brazil’s Federal District: Integrating Physical, Mechanical, and Hydraulic Parameters

The collapsible soils of Brazil’s Federal District are characterized by a porous structure and a marked sensitivity to moisture variation, presenting significant challenges to geotechnical engineering. This study investigates the physical, mechanical, and hydraulic parameters governing the behavior of these soils under varying stress and saturation conditions. To this end, a comprehensive suite of laboratory tests was conducted, including direct shear, triaxial, and oedometer tests with inundation, as well as suction measurements using the filter paper method and the WP4C device. The soil-water characteristic curve obtained confirmed the reliability of the experimental methods and underscored the influence of the bimodal pore structure on shear strength. The findings emphasize the critical importance of jointly analyzing physical, mechanical, and hydraulic parameters to enable more accurate assessments, thereby enhancing the safety and efficiency of infrastructure design in regions underlain by collapsible tropical soils.