Banca de DEFESA: TAHYARA BARBALHO FONTOURA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : TAHYARA BARBALHO FONTOURA
DATE: 31/08/2022
TIME: 14:00
LOCAL: Pos Graduação Engenharia Civil
TITLE:

Geological-Geotechnical Characterization and Susceptibility ad Stability Analysis of the “Alto de Santa Tereza” Slope in Recife-PE

KEY WORDS:

Geological-geotechnical characterization, Slope stability, SINMAP, SHALSTAB, TRIGRS

PAGES: 450
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

In large Brazilian metropolises, there are high levels of socioeconomic segregation and the low-income population ends up being driven to places further away from the city, forming peripheries. The city of Recife is an example of this. The absence of specific urban planning has subjected a large part of the population to experience landslide problems, and flooding of riverside communities, among other situations. Due to the increase in the incidence of mass movements on slopes during the rainy season, it is important to predict the areas that may present processes of soil instability. Therefore, this work has as its main objective the geological-geotechnical characterization and the analysis of susceptibility and stability of the Alto de Santa Tereza hillside, located in the neighborhood of Passarinho, in Recife. The geotechnical characterization was carried out through a test campaign carried out at the Soil and Instrumentation Laboratory of UFPE, among them, physical characterization tests (granulometry, sedimentation, LL, LP, real grain density), tests to obtain the resistance parameters (Direct Shear and Triaxial Compression), tests to obtain the characteristic curve (filter paper, tension table and vacuum desiccator) and tests to obtain the permeability coefficient (Triflex and Guelph). Chemical (FRX), mineralogical (XRD), and microstructural (SEM) tests were also carried out for more detailed characterization and investigation of the weathering process of the slope soils. Instrumentation was performed by installing a rain gauge and inclinometers along the sounding profile to monitor the existence of any signs of landslides. Landslide susceptibility maps were developed based on the results of the TRIGRS, SHALSTAB, and SINMAP mathematical models. The analyzes were divided into 2 Scenarios for each model varying the parameters according to the results of the direct shear and triaxial test and at 4 different depths. In the TRIGRS model, in addition to the saturated infiltration mode, analyzes were also performed in the unsaturated infiltration mode. The sensitivity of the model results was analyzed using the LRclass method and compared with each other. Stability and flow analyzes used SLOPE/W and SEEP/W software. The analyzes were divided into 3 Scenarios: saturated flow, unsaturated flow with estimated ϕb, and unsaturated flow with ϕb experimentally determined. For this, 3 methods were used: Bishop, Morgenstern and Price and Spencer. The geological formation of the soil of the slope is characterized by the Barreiras Formation, presenting mostly sand with prismatic and spherical quartz grains, sub-angular to angular. The inclinometers show that there is no sign of slope movement. The results of the geotechnical parameters are in agreement with others obtained in soils of the Barreiras Formation in the areas of the Metropolitan Region of Recife. The susceptibility analysis showed that the model with the best accuracy in predicting landslides is SINMAP, followed by TRIGRS. SHALSTAB presented %LRclass below 70%. The stability analyzes showed that the safety factors for the 3 methods adopted are similar. The analysis using estimated ϕb obtained results similar to those with determined ϕb.

BANKING MEMBERS:
Presidente - 2749584 - IGOR FERNANDES GOMES
Externo ao Programa - 1549099 - ROBSON RIBEIRO LIMA
Externo ao Programa - 1162231 - SAUL BARBOSA GUEDES
Externo à Instituição - RICARDO NASCIMENTO FLORES SEVERO - IFRN
Externo à Instituição - RODOLFO MOREDA MENDES