Banca de DEFESA: Max Gabriel Timo Barbosa

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Max Gabriel Timo Barbosa
DATE: 02/05/2023
TIME: 14:00
LOCAL: Online-Teams
TITLE:

Study of the pulllout resistance of soil nails performed by means of the sectorized post grouting technique

KEY WORDS:

1. Soil Nailing 2. Soil grouting 3. Pullout Resistance 4. Sectorized Post Grouting

PAGES: 237
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Geotécnica
SPECIALTY: Mecânicas dos Solos
SUMMARY:

This thesis presents results of investigations carried out in real scale of the soil-nail interaction, especially in soil nails executed with sectored post grouting, through sub-horizontal and vertical pullout tests in real works and experimental campaign of soil nails. It was verified the sectored reinjection technique, a technique developed in Brazil for the execution of soil nails, obtained better results than the gravity grouted soil nails. By analyzing seven works executed in real scale, it was possible to propose an empirical model for estimating the pullout resistance of soil nails executed by sectorized post grouting. To validate the empirical model and observe executive influences of soil nail not investigated in works with post grouted soil nails, in addition to proposing a method of selection of executive technique of soil nails and previous pullout test alternatives as suggested by Seo et al. (2012), an experimental campaign was carried out in the porous clay of Brasília. In this campaign, the exhumation of soil nails was carried out to investigate the influence of the mean angle of surface roughness of the soil nails and the average exhumed diameters on the results of the pullout tests of the different executive techniques studied. After analyzing the results of the campaign, it was observed that drilling with water provided better results for all types of soil nails in the case of the characteristic soil of Brasilia and the use of additives in cement grouts can generate worse results due to the smoother interface and because of grouts with lower compressive strength, an important influence on pullout resistance. In addition to verifying the drilling method, superior results were observed in terms of pullout resistance for post grouted soil nails in relation to the other types of injection methodologies studied, with the proposed empirical model conservatively predicting the results of the pullout tests of post grouted soil nails. With the qualitative and quantitative validation of the sectorized post grouting, in real works prior to this thesis and in the field, the empirical model proposed was used satisfactorily in soil nail retaining walls in the state of Pará, Brazil, a place with a high number of retaining walls in soil nailing currently in execution. Furthermore, when comparing the subhorizontal and vertical pullout tests in the same location, it was verified that the results within the standard deviation of the mean of both test orientations allow not only the use of the empirical model proposed in this thesis, but also the use of vertical pullout tests as viable tools in the design and execution of post grouted soil nails.

BANKING MEMBERS:
Externo à Instituição - PEDRO WELLINGTON GONÇALVES DO NASCIMENTO TEIXEIRA - USP
Externo à Instituição - FELIPE GOBBI SILVEIRA
Presidente - 404827 - ANDRE PACHECO DE ASSIS
Interno - 404375 - ENNIO MARQUES PALMEIRA
Interno - 2161425 - JUAN FELIX RODRIGUEZ REBOLLEDO