Influência da variação de energia de compactação nos parâmetros de massa específica seca máxima e umidade ótima do solo superficial de Pato Branco - PR

Abstract

Soil compaction is a fundamental step in geotechnical engineering, acting directly on the improvement of mechanical properties, reduction of compressibility, and increase in the bearing capacity of soil structures and pavements. Given the variability of residual soils in southwest Paraná, establishing local parameters for technological control is necessary. This study aimed to evaluate the influence of compaction energy variation on the maximum dry unit weight and optimum moisture content parameters of the surface soil in the municipality of Pato Branco - PR. The methodology was based on the standard guidelines of ABNT NBR 7182:2025 for conducting compaction tests under three different energy levels: Standard, Intermediate, and Modified. The initial physical characterization revealed a predominantly fine-grained material, with a clay content of 82.0%, classified as low to medium plasticity inorganic clay (CL) by the Unified Soil Classification System (USCS). The experimental results confirmed the theoretical behavior established in geotechnical literature, characterized by the progressive displacement of the compaction curves towards the upper left quadrant of the Cartesian plane as the energy input increased. The increment in mechanical effort promoted a reduction in void volume through the expulsion of air contained in the pores, culminating in an increase in the maximum dry unit weight and a consequent reduction in the optimum moisture content, since lower volumes of water were required for interparticle lubrication. Additionally, the comparative analysis with granular samples showed that the high specific surface area and structural water retention of the local clay matrix impose higher water demands and lower dry densities when compared to soils with sandy behavior. It is concluded that the mapping of these regional specificities accurately supports project guidelines and optimizes the technological control of local civil works.