Banca de DEFESA: ANDERSON DANTAS DE MORAIS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANDERSON DANTAS DE MORAIS
DATE: 02/03/2020
TIME: 15:00
LOCAL: Auditório do CT
TITLE:

GEOTECHNICAL PROPERTIES OF THE BARREIRAS
FORMATION SEDIMENTS AND ESTABILITY ANLYSES IN
CLIFFS CONSIDERING UNSATURATED SOIL CONDITION: CASE

STUDY IN BARRA DE TABATINGA / RN.

KEY WORDS:

Cliff; Barreiras Formation; Geotechnical properties; Stability.

PAGES: 152
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

In the state of Rio Grande do Norte exists outcrops of cliffs that belongs to the Barreiras Formation, which cities and infrastructure works are developed on. In this region, mass movements are reported in relevant proportions, especially in rainy season. The development of coastal cities and the growing tourism market in this area has demanded the study of the cliffs and their material, so that new engineering projects are safely implemented. The aims of this work were to study the geotechnical properties of the Barreiras Formation soils that make up the Barra de Tabatinga / RN beach cliff and to evaluate the stability of the cliff from the deterministic point of view. The studied cliff was divided into three predominant soils, which are located at the base (AM-01), middle (AM-02) and top (AM-03) layers. In these soils, were performed characterization tests (geotechnical, chemical and mineralogical), tests to determine the soil-water retention curve, permeability tests, triaxial and diametral compression tests under saturated and unsaturated conditions. Considering the Unified Soil Classification System (SUCS), samples AM-01, AM-02 and AM-03 were respectively classified as similar in behavior to silt-clay sand (SM-SC), silt sand (SM) and poorly graded sand (SP). The chemical analysis identified oxides of silicon, aluminum and iron in higher percentages. Regarding the mineralogical analyzes, the presence of Quartz and Kaolinite were detected in all samples. Samples AM-01 and AM-02 showed bimodal soil-water retention curves, unlike the top sample, which presented unimodal fit. In addition, all of them presented close to zero cohesion and angle of friction around 30° in the saturated condition. However, when unsaturated, the strength parameters increased considerably, especially the cohesion. In unsaturated condition, the top soil is the least shear and tensile strength. Concerning stability analyzes, these were performed in Slope / W (Geostudio, 2012) considering three different hypotheses: fully saturated cliff (hypothesis 01); totally dry cliff (hypothesis 02) and the water infiltration on cliff top (hypothesis 03) through numerical modeling in Seep / W (Geostudio, 2012). Hypothesis 03 attempted to approach the actual critical condition, trying to consider the effect of rain on cliff stability. Therefore, it was concluded that for the considered rain, the cliff rupture is characterized, since FS = 1 is reached. Moreover, it was observed that the rupture occurs completely through the top layer material and can reach depths of up to 8 meters. 

BANKING MEMBERS:
Interno - 2085750 - FAGNER ALEXANDRE NUNES DE FRANCA
Presidente - 1149451 - OLAVO FRANCISCO DOS SANTOS JUNIOR
Interno - 1692497 - OSVALDO DE FREITAS NETO
Externo à Instituição - RICARDO NASCIMENTO FLORES SEVERO - IFRN