Influência da sucção na erodibilidade de um solo argiloso compactado da formação Guabirotuba

Abstract

The Guabirotuba Formation has characteristics that make it susceptible to the development of erosion processes, and when accelerated by anthropic action, they impact the environmental and socioeconomic sphere. Soil susceptibility to erosion can be represented by the erodibility parameter (K), which is related to the suction acting on the unsaturated soil structure. In this context, the present research aimed to evaluate the influence of suction on the erodibility of compacted clayey soil from the Guabirotuba Formation. The soil erodibility determination test was carried out with Inderbitzen equipment. Soil characterization was carried out through granulometry, real specific mass of the grains, Atterberg limits, X-ray fluorescence (FRX), X-ray diffraction (XRD), scanning electron microscopy (SEM), and compaction tests, in standard, intermediate effort, and modified effort. The variable load permeability test was carried out to analyze the conductivity of the compacted hydraulic soil. Soil water characteristic curves for compacted soil at the three efforts were obtained from the Filter Paper Method tests. The erodibility test was carried out with specimens compacted at the three maximum dry apparent specific masses of the compaction curves (1.48 g/cm³, 1.57 g/cm³, and 1.66 g/cm³) and at the degrees of saturation of 20%, 50%, and optimal saturation. The variation in soil compaction density altered the shape of the characteristic curve, which tends towards a unimodal shape due to the reduction in the void ratio. Soil permeability decreased markedly for degrees of saturation corresponding to the characteristic curve’s desaturation stretch at 1.48 g/cm³, 1.57 g/cm³, and 1.66 g/cm³. Soil mass loss was influenced by the degree of saturation, density, and slope, with the degree of saturation being the most significant factor. Soil resistance to erosion was shown to be lower for the 50% saturation degree, which may be related to the reduction in the unsaturated permeability coefficient of the soil. In summary, it is confirmed that the degree of saturation of the soil significantly impacts its resistance to erosion, being more susceptible to disruption during the continuous phase of air in the pores.