EM - Escola de Minas

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A dual search‐based EPR with self‐adaptive ofspring creation and compromise programming model selection.
(2021) Gomes, Guilherme José Cunha; Gomes, Ruan Gonçalves de Souza; Vargas Júnior, Eurípedes do Amaral
Evolutionary polynomial regression (EPR) is extensively used in engineering for soil properties modeling. This grey-box technique uses evolutionary computing to produce simple, transparent and well-structured models in the form of polynomial equations that best explain the observed data. A key task is then to determine mathematical structures for modeling physical phenomena and to select the optimal EPR model. This requires an algorithm to search through the model structure space and successfully produce feasible solutions that honor a set of statistical metrics. The complexity of EPR models increases greatly, however, with the number of polynomial terms used to tune these models. In this paper, we propose an alternative EPR for modeling complex soil properties. We implement a dual search-based EPR with self-adaptive ofspring creation as model structure search strategy and couple a compromise programming tool to select a model that is preferred statistically relative to models with diferent polynomial terms. We illustrate our method using real-world data to improve predictions of optimal moisture content and creep index for soils. Our results demonstrate that the models derived using the proposed methodology can predict soil properties with adequate accuracy, physical meaning and lower number of parameters and input variables.
Phosphatized volcanic soils of Fernando de Noronha Island, Brazil : paleoclimates and landscape evolution.
(2020) Silveira, Jonas Carvalho; Oliveira, Fabio Soares; Schaefer, Carlos Ernesto Gonçalves Reynaud; Varajão, Angélica Fortes Drummond Chicarino; Varajão, Cesar Augusto Chicarino; Senra, Eduardo Osório
Volcanic oceanic islands host soils that may hold important paleo-environmental proxies, based on vegetation and faunal evidences coupled with pedological and geomorphological indicators. In this regard, the main Brazilian oceanic island of Fernando de Noronha (FNI) still lacks a deeper and more complete analysis of its climatic history and soil evolution. We select and collect representative FNI soils to interpret their chemical, physical and mineralogical properties and to explain their changing pedogenesis and geomorphic balance, aiming at revealing the environmental and landscape evolutionary history of this island. Ten soil pedons on phonolites, ankaratrites and the associated pyroclastic rocks were collected in June/2018. Six profiles were classified as Inceptisols, one as Entisol, one as Mollisol, one as Vertisol and another as the first Oxisol ever described in a Brazilian oceanic island. The pH ranged between 5.0 and 6.0 in the more developed, dystrophic and Al-saturated soils, whereas alkaline pHs were found in the eutrophic and Na-rich pedons. For the latter group, chemical and physical attributes are closely associated with the parent material composition, whereas in the former, present day soil features overprint paleoweathered regoliths and former pedogenetic processes. High concentrations of available phosphorus (P) were observed in all soils and horizons, even at depths greater than 150 cm, and P forms were detected as amorphous or poorly-crystalline phosphates (Al, Fe, Na, Ca and K). High- and low-activity clay minerals coexist, combined with gibbsite and unstable primary minerals, indicating the polygenetic nature of FNI soils. A combined pedogeomorphological analysis indicated the existence of a high paleoweathered plateau with relict soils, and erosional surfaces hosting younger soils. Results showed the succession of at least three distinct main paleoclimates since the Pliocene and a post-magmatic model for landscape evolution. The unreported, widespread and intense phosphatization of all soils and paleosurfaces is attributed to a past large population of birds nesting all over the island, corroborating old historical records of the island’s early occupation. Report the occurrence of Brazil’s first ornithogenic Oxisol with more than 500 mg/ kg of bioavailable P.
A sustainability-oriented framework for the application of industrial byproducts to the base layers of low-volume roads.
(2021) Gomes, Guilherme José Cunha; Magalhães, Adair José de; Rocha, Fabiano Lucindo Lima da; Fonseca, Alberto de Freitas Castro
Roadway engineering works typically rely on the utilization of natural aggregates as building materials. However, growing pressures for sustainable roads are highlighting the importance of replacing virgin materials with industrial byproducts. Constructors worldwide are trying to select optimum soilbyproduct mixtures that have a fair trade-off between engineering properties, environmental impacts and material costs. This requires a multi-objective analysis to explore feasible mixtures that honor a set of preferences to mathematically identify the best compromised soil-byproduct mixture. In this paper, a sustainability-oriented framework is proposed for selecting optimum soil-byproduct proportions for unbound base layers of unpaved roads. A compromise programming tool is implemented to select a mixture that is statistically preferred over mixtures with different byproduct contents. The method is illustrated using technical, economic and environmental indicators that are easily measurable. Investigations are performed for different decision-making perspectives including the constructor’s, contractor’s and the environment’s viewpoints. Two byproducts from the steel industry are mixed in different proportions from 50% to 80% by weight with a clayey soil. The optimum mixture was obtained at a proportion of 70% byproduct and 30% clay. Monte Carlo simulations and sensitivity analysis of transport scenarios further supported this conclusion. Results demonstrate that mixture selection based only on strength properties provides inadequate optimum from a sustainable standpoint. The proposed framework can help road constructors incorporate environmentally-friendly materials in a cost-effective way, while maintaining the technical quality of base layers.

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