Banca de DEFESA: Narayana Saniele Massocco

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Narayana Saniele Massocco
DATE: 27/03/2023
TIME: 14:00
LOCAL: TEAMS
TITLE:

" Structure effect on compressibility and shear strength of a lateritic soil"

KEY WORDS:

Double porosity soils,  Hydromechanical behavior, Microstructure, stress-strain, dilatation, lateritic soil.

PAGES: 149
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Geotécnica
SPECIALTY: Mecânicas dos Solos
SUMMARY:

One of the main factors that influence the soil behavior is the structure in which a soil was formed. Therefore, studies have been developed in order to identify how the microstructure affects behavior. However, it is known that in lateritic soils aspects such as aggregation, cementation, pore distribution impact the hydraulic and mechanical response. In this sense, this work aims to verify the influence of these structural elements on the hydraulic and mechanical behavior of a metastable lateritic soil. The investigation proposed analyzes based on samples that have different structures: intact, compacted (in Normal and Modified Proctor energy) and reconstituted (with the use of dispersing agents such as distilled water and sodium hexametaphosphate) due to its bimodal structure. The hydraulic and microstructural tests, at first, made it possible to understand how these different samples behave and how they are structurally arranged. From this, it was possible to establish a quantitative, semi-quantitative and qualitative analysis of the pore distribution using MIP, SEM and granulometry tests. It was identified that the samples in the Normal Proctor energy have evident macropores, the modified energy has only micropores, and the reconstituted samples have reduced aggregation as well as the effect of the dispersing agent with the use of hexametaphosphate. These analyzes together with the consolidation tests made it possible to define the possible intrinsic state of the soil and quantify it in macropores and micropores. Finally, the direct shear tests provided, in addition to behavior analysis, to verify the arrangement of the aggregations after rupture from the removal of samples from a sheared band, which were sent to MIP and SEM tests at tensions of 70 kPa and 300 kPa. This made it possible to verify changes in the form of aggregation as well as orientation after shearing. In general, it is concluded that the effect of compaction on the structure is associated with the observation of dilatation and cohesive intercept values different from zero.

BANKING MEMBERS:
Presidente - 1549489 - MANOEL PORFIRIO CORDAO NETO
Interno - 2161425 - JUAN FELIX RODRIGUEZ REBOLLEDO
Interno - 3132829 - RAFAEL CERQUEIRA SILVA
Externo à Instituição - Sandro Lemos Machado - UFBA
Externa à Instituição - Bruna de Carvalho Faria Lima Lopes