Studying of the Strength and Stiffness of an Unsaturated Tropical Soil Profile

• Grant number: 17/23174-5
• Support Opportunities: Regular Research Grants
• Duration: June 01, 2018 - November 30, 2020
• Field of knowledge: Engineering - Civil Engineering - Geotechnical Engineering
• Principal Investigator: Heraldo Luiz Giacheti
• Grantee: Heraldo Luiz Giacheti
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil
• Associated researchers: Osvaldo Luís Manzoli ; Roger Augusto Rodrigues

Abstract

The occurrence of pedological changes and the evolution of tropical soil profiles is common in Brazil due to the intensity of the climatic events and the physical-chemical processes that act on these soils. The study of the geomechanical behavior of these soils is limited based on laboratory tests since in most cases the testing of samples collected from a depth selected as representative of a horizon or even the entire profile. In this research project, it is intended to study the geomechanical behavior of a tropical unsaturated soil profile of known stratigraphy, subject to different degrees of pedogenetic evolution. The objective of this research is to contribute to a better understanding of the variation of strength and stiffness parameters in unsaturated soil profiles and evaluating the effect of factors such as suction, net normal stress, in situ stress, physical properties and indices, evolution and soil genesis. Edometric and instrumented triaxial tests, both with suction control, will be performed and interpreted in undisturbed samples collected in three specific regions of the soil profile: a well-developed colluvium (between 1.5 and 5.0m depth); undeveloped colluvium (between 10,0 and 13,0m depth) and probably the residual sandstone (16.0 and 17.0 m depth). Previous researches show little variation in the geomechanical parameters between 1.0 to 5.0m depth interval. Therefore, it is necessary to extend this study up to 17.0m depth, where large profile modifications are expected. The integrated interpretation of the entire laboratorial test campaign will serve as a basis for a more complete and adequate analysis of the influence of the factors that affect the behavior of this material, especially the strength and stiffness, highlighting factors such as genesis, suction and history of stress. In addition, it is also an objective of this research to contribute with the database of geotechnical parameters of the studied site with the perspective of modeling the test data. It will allow a better identification of the parameters which characterizes the soil behavior as well as a better interpretation of in situ penetration tests in tropical unsaturated soils. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

JEFERSON BRITO FERNANDES; BRENO PADOVEZI ROCHA; HERALDO LUIZ GIACHETI. Maximum shear modulus and modulus degradation curves of an unsaturated tropical soil. Soils and Rocks, v. 46, n. 2, 2023-04-28. (15/17260-0, 17/23174-5)

JEFERSON BRITO FERNANDES; ALFREDO LOPES SAAB; BRENO PADOVEZI ROCHA; ROGER AUGUSTO RODRIGUES; PAULO CÉSAR LODI; HERALDO LUIZ GIACHETI. Geomechanical parameters in the active zone of an unsaturated tropical soil site via laboratory tests. Soils and Rocks, v. 45, n. 4, 2022-11-25. (17/23174-5)