Estudo do comportamento hidromecânico de misturas de solo areno argiloso com fibras de polipropileno

Abstract

The use of polypropylene fibers to reinforce soils is applicable when the soil in its natural state does not have the geotechnical properties necessary to support the expected field stresses. Fibers can drive improvements such as increased shear strength and increased soil permeability. The objective of this work is to study the hydromechanical behavior of a sandy-clayey soil, used as a landfill cover material in the State of Ceará, with the insertion of polypropylene fibers, with different fiber contents and lengths, and to verify the influence on the geotechnical parameters of the soil cover with the insertion of fibers. As part of the research, laboratory tests for geotechnical and mineralogical characterization were done. Polypropylene fibers of 6 mm and 12 mm in length were used, at the contents of 0, 0.25, 0.50, 0.75, 1 and 1.25% in relation to the weight of the dry soil. A reduction in the dry apparent specific weight and an increase in the optimum moisture content (except for the 0.25% and 0.75% contents for the 12 mm fiber) were observed with the increase in fiber inclusion. With the addition of more fibers there was an increase in soil permeability, both for the 6 mm and 12 mm fibers, even with the increase in permeability the composite can still be used as a landfill cover layer. The combinations with the best shear strength performances were for the 0.75% content for the 6 mm fiber and the 1.25% content for the 12 mm fiber. Scanning electron microscopy shows that for the levels of 0.75% (6 mm) and 1.25% (12 mm), the adhesion between the soil and the fiber occurred adequately, which justifies these being the levels that provided the greatest gain in soil resistance. Considering the relevance of the use of polymeric fibers for soil reinforcement, this work aims to contribute to the understanding of the mechanical behavior of sandy clayey soils reinforced with polypropylene fibers, evaluating the performance of the soil reinforced with fibers by analyzing the variation in contents and lengths.