Banca de DEFESA: DELLANE STEPHANI CARVALHO DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DELLANE STEPHANI CARVALHO DOS SANTOS
DATE: 16/08/2023
TIME: 08:00
LOCAL: Online-Teams
TITLE:

Behaviour of geotextile filters in internally unstable soils under confinement

KEY WORDS:

Filtration, Nonwoven Geotextile, Internally Unstable Soils.

PAGES: 116
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Geotécnica
SUMMARY:

This dissertation addressed the study of the filtering behavior of non-woven geotextiles in internally unstable soil under confinement. Permeability tests were carried out under constant head conditions using a permeameter equipped with a device for the application of vertical stresses. The non-woven geotextiles tested had masses per unit area of 200, 400 and 600 g/m², the soil was composed of sand plus different percentages (0, 10, 20 and 40%) of fine material and the applied vertical stresses were 0, 25 and 100 kPa. The drainage materials under the geosynthetic filter were steel spheres of 15 mm in diameter, with ratios between spacing (s) and sphere diameter (d) equal to 1 or 2, or just a perforated plate. A series of filtration tests was conducted under hydraulic gradients of 1 and 10. The results were discussed in terms of the permeability coefficient of the soil-geotextile system (ksg). At the end of the tests, the grain size distribution curves of the material at the base of the soil sample and of the material that impregnated or passed through the geotextile filter were obtained using a laser grain size analyser. The degrees of impregnation of the geotextiles were obtained after the permeability tests. In addition, permeability tests were also performed on the 200 g/m² geotextile after filtration tests. Tests with samples of sand plus 40% of fines with 5, 10 and 15 cm height were performed in order to evaluate whether the height of the specimen influenced the filter behavior. Sagging of the geotextiles in the void spaces between the spheres were also assessed. It was observed that the vertical stress at the top of the samples,the hydraulic gradient, the increase in the mass per unit area of the geotextile and the tests with only the perforated plate under the geosynthetic tended to reduce the permeability of the soil-geotextile system. Increasing the spacing between the spheres decreased ksg and favoured the formation of a blinding layer on the filter surface.

COMMITTEE MEMBERS:
Externo à Instituição - EDER CARLOS GUEDES DOS SANTOS - UFG
Presidente - 404375 - ENNIO MARQUES PALMEIRA
Interno - 2517970 - GREGORIO LUIS SILVA ARAUJO
Interno - 1122864 - RENATO PINTO DA CUNHA