Modelagem geográfica para caracterização e predição de solos moles direcionada para projetos de infraestrutura

Abstract

Knowledge of soil characteristics is crucial for territorial planning. The soft deposits, traditionally known as soft soils, refer to sedimentary soil with low resistance to penetration, in which clay provides the characteristics of the soil. Although the soil may present different characteristics that might lead to its rating as soft, these are technical issues restricted to the fields of Geotechnical Studies. Infrastructure projects, specially transport ones, such as freeways and railways, are traditionally demanding on information about soft soil occurrence, be it by the geographical coverage of the roads or by the need to count on appropriate soil to receive the road infrastructure and undercarriages. Traditionally, the transport engineering is based on Geotechniques for specific analysis in soft soil areas, which are vital, albeit costly. Therefore, this paper presents a model exploring an indexing key to classify between pedological and geotechnical properties of soils, which resulted in a predictive map of the occurrence of soft soils in Brazil. Although developed on a 1:5,000,000 scale (EMBRAPA), the model was tested on pedological maps with 1: 250,000 scale (EMATER) and validated by field analysis on a section of the North-South railway in the state of Goiás. The presented model proved sound, as it can be applied in larger and regional scales. It was also identified that the soils which show a higher potential of soft soil are those with a predominance of expansive 2:1 minerals, usually poorly drained and shallow such as cambisol, gleysol and neosol. It was observed, also, that the potential of occurrence of soft soil in Brazil is around 29% of the territory. Further studies of this nature are important, especially in the central area of the country, of which there is a considerable lack of data on this material.