Geomechanical and Hydraulic Behavior of Impermeable Layers for Earthworks

Objective: The objective of this study is to investigate the mechanical and hydraulic behavior of fine sandy soil mixtures from the Coastal Plain of Rio Grande do Sul with bentonite, assessing their technical feasibility as an impermeable layer for earthwork projects. Theoretical Framework: El marco teórico explora la impermeabilización de vertederos sanitarios, destacando la eficacia de los liners para contener contaminantes y el uso de bentonita como aditivo para suelos granulares. Estudios previos señalan mejoras en la conductividad hidráulica y la plasticidad de mezclas de suelo-bentonita, especialmente en regiones con escasez de materiales arcillosos de alta calidad. Method: The method includes laboratory tests with natural soil and mixtures containing different bentonite contents. Physical, granulometric, plasticity, compaction, hydraulic conductivity, and mechanical resistance properties were evaluated. Results and Discussion: The natural soil proved unsuitable for use as an impermeable layer. The results show that the addition of bentonite significantly improved the soil's hydraulic conductivity, with 6% by dry weight achieving values suitable for impermeable layers. However, increasing bentonite content reduced the friction angle, indicating a decrease in mechanical strength. Research Implications: The research highlights the potential of soil-bentonite mixtures as a sustainable solution for impermeable layers in earthwork projects, particularly in regions with limited availability of clayey soils. The results provide technical support for the use of local materials, contributing to the feasibility of environmental engineering projects tailored to regional characteristics. Originality/Value: The research is original in exploring soil-bentonite mixtures as a sustainable solution for impermeable layers in coastal plains, a region with scarce suitable clayey soils. Its contribution lies in the technical evaluation of local materials, promoting innovative and environmentally adapted alternatives for engineering projects in challenging contexts.