Banca de DEFESA: Amandda Lara Moreira Braga

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Amandda Lara Moreira Braga
DATE: 24/10/2022
TIME: 10:00
LOCAL: Online-Teams
TITLE:

STUDY OF THE INFLUENCE OF THE SIZE AND SHAPE OF PARTICLES ON THE MECHANICAL BEHAVIOR OF GRANULAR SOILS.

KEY WORDS:

Granular Materials, Morphology, Size, Friction Angle and Repouse Angle

PAGES: 111
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

• The studies of the mechanical parameters of granular materials have been, simply, based on the continuum. The simplicity of studying the environment through phenomenological constitutive models and representative volume tests, made it impossible to analyze the characteristics of the samples at the particulate level. With the development of new tools such as supercomputers and image analyzers, the discrete element method, which is based on the interaction of grains, has been gaining strength. In this approach it is possible to consider the microscopic characteristics of the particles in the evaluation of the mechanical behavior of granular materials. In this work, the influence of size, shape and surface texture, at the particle level, on the angles of repose and friction of granules is studied. For this, granulometric and morphological characterization tests were carried out, evidencing parameters such as D50, sphericity, circularity, roundness. Through the tests of angle of repose, direct shear and saturated CD triaxial, the mentioned angles were determined. The experimental results obtained showed the same trend of behavior of the materials in relation to the resistant angles. The characterization of the particles showed that manufactured materials, spheres and polyhedrons, are similar in relation to surface texture while the sands are distinguished in the sample group itself. The sizes were different as well as the shape indices, although the spheres had similar indices. In this research, the size parameters did not show a good trend in relation to the angles. Among the shape indices, the roundness had the best coefficient of determination. Using the roundness index, equations from the literature were selected that had it as a variable. In addition to tests with existing equations, equations with one and two variables were also proposed for each type of angle studied. The chosen parameters were the roundness, since it was better related to the angles, and the D50 (for friction in direct shear), eMÁX (angle of repose) and D10 (friction in the saturated CD triaxial), in the functions of two variables. Finally, statistical analyzes were performed with the equations from the literature and the proposals verifying that the equations of this study had a better index of precision and accuracy.

BANKING MEMBERS:
Externo à Instituição - JOAO PAULO SOUZA SILVA - UFG
Interno - 1549489 - MANOEL PORFIRIO CORDAO NETO
Presidente - 404227 - MARCIO MUNIZ DE FARIAS
Interno - 3132829 - RAFAEL CERQUEIRA SILVA