Modelagem numérica do comportamento mecânico do solo após preparo sob tráfego de veículos na cultura de cana-de-açúcar

Abstract

Agricultural soil compaction is an issue that has been intensified over the last decades due to crop systems mechanization, driven by market’s competitiveness. Sugarcane is one of the main crops that is affected by this issue, mainly due to mechanized harvest and soil preparation for replanting. In order to mitigate soil compaction, it is essential to understand soil mechanical behavior, how machinery-based tension are spread through soil, and their consequences to soil structure. Mathematical models applied to this phenomenon are a great alternative and simply way to monitor and understand this process. Compaction models are divided into pseudo-analytical models, which come from Boussinesq equation, and numerical models, which use approximation methods such as finite element, finite difference, finite volume methods, etc. The aim of this study was to evaluate soil mechanical behavior after preparation under vehicle traffic in a sugarcane field, applying finite element method through numerical simulations assuming the elasticplastic model, CamCley Modified based on soil critical states theory. Governing equations of the studied issue are based on continuous media mechanics. Five axle configurations were evaluated for three different soil water content scenarios. The output variables were as follows: vertical stress distribution, porosity, pre-compression stress and displacement. It was possible to conclude that all vehicles caused additional compaction to the 0-20 cm layer. Soil water content was a determining factor to increase compaction risk. There was a significant increase in porosity in the region between wheels, which is the same as the crop root system concentration area. Vehicle traffic control within a cultivation plot is a great alternative to control compaction processes.